Prompt:
FEN: r2r2k1/pbq2p1p/1p2pnp1/2b5/1P1Np3/P1P1P1PP/2Q2PB1/R1B1R1K1 b - - 0 16
For square a4, give the FEN row-from-top and file index.

Answer format: return exactly "<square>: file=<file>; rank=<rank>; fen_row_from_top=<1-8>; file_index=<1-8>".

a4: file=a; rank=4; fen_row_from_top=5; file_index=1


Prompt:
FEN: 1k1r1b1r/2pq3p/p1n1p2Q/1p5p/3PP3/1BN5/PPP3P1/1K1R3R w - -
Compressed rank 6 row: p1n1p2Q
Expand it into file cells a through h.

Answer format: return exactly "rank N: a=<cell>; b=<cell>; ...; h=<cell>".


Prompt:
Rank 7 row before: pp3ppp
File g changes from p to 1. Rewrite the compressed row.

Answer format: return exactly "rank N: <before-row> -> <after-row>".


Prompt:
Board FEN before: rn2k1nr/pp1b1pRp/8/3N4/3P4/4B3/PPP1KP2/R2Q3q
Apply square edits: e8 k->1; f8 1->k
Return the resulting board FEN only.

Answer format: return exactly "Result board FEN: <piece-placement-field>".

Result board FEN: rn3knr/pp1b1pRp/8/3N4/3P4/4B3/PPP1KP2/R2Q3q


Prompt:
Starting FEN: 3r2r1/1p5k/pb1P1p1p/2pR4/1PP3b1/P4N2/1B3PP1/4R1K1 w - - 3 28
Move: e1e4
List the square lookups and rank edits.

Answer format: return exactly three lines starting "Lookup:", "Squares:", and "Ranks:"; do not include Result FEN.

Lookup: e1=white rook; e4=empty.
Squares: e1 white rook->empty; e4 empty->white rook.
Ranks: rank 1 e R->1; rank 4 e 1->R.


Prompt:
Starting FEN: rnb2rk1/pp2qppp/2p5/3p3n/3P4/2NBPN2/PP3PPP/R2QK2R w KQ - 0 1
Move: d3g6
Use square lookups and rank edits to assemble the resulting full FEN.
State needed for full FEN:
Side to move: white
Castling rights: KQ
En passant: none
Halfmove clock: 0
Fullmove number: 1

Answer format: include the edit trace and exactly one final line "Result FEN: <complete six-field FEN>".

Move 1: white bishop d3g6.
Lookup: d3=white bishop; g6=empty.
Squares: d3 white bishop->empty; g6 empty->white bishop.
Ranks: rank 3 d B->1; rank 6 g 1->B.
Result FEN: rnb2rk1/pp2qppp/2p3B1/3p3n/3P4/2N1PN2/PP3PPP/R2QK2R b KQ - 1 1


Prompt:
Starting FEN: 3r1rk1/pp2bppp/3q4/2pnN3/P7/1PBP4/1P1QRPPP/4R1K1 w - - 7 18
Move: e1f1
Rewrite the affected compressed FEN rank rows and give Result FEN.
State needed for full FEN:
Side to move: white
Castling rights: none
En passant: none
Halfmove clock: 7
Fullmove number: 18

Answer format: first line starts "Rows:" and final line is "Result FEN: <complete six-field FEN>".

Rows: rank 1 4R1K1->5RK1.
Result FEN: 3r1rk1/pp2bppp/3q4/2pnN3/P7/1PBP4/1P1QRPPP/5RK1 b - - 8 18


Prompt:
Starting FEN: r4rk1/1pqbbpp1/p1p1pn1p/4N3/3P1P2/P1N4P/1PQ2PP1/1B1R1RK1 b - - 0 1
After the moves h6h5, what is the resulting position?
State needed for full FEN:
Side to move: black
Castling rights: none
En passant: none
Halfmove clock: 0
Fullmove number: 1

Answer format: return exactly "Result FEN: <complete six-field FEN>".

Result FEN: r4rk1/1pqbbpp1/p1p1pn2/4N2p/3P1P2/P1N4P/1PQ2PP1/1B1R1RK1 w - - 0 2


Prompt:
FEN: r1bqkb1r/pppn1pp1/3p1n1p/4p3/3PP3/2NB1N2/PPP2PPP/R1BQ1RK1 b kq - 4 6
List the material inventory by side and piece type.

Answer format: return exactly two lines starting "White inventory:" and "Black inventory:".

White inventory: king=g1; queen=d1; rook=a1,f1; bishop=c1,d3; knight=c3,f3; pawn=a2,b2,c2,f2,g2,h2,d4,e4.
Black inventory: king=e8; queen=d8; rook=a8,h8; bishop=c8,f8; knight=f6,d7; pawn=e5,d6,h6,a7,b7,c7,f7,g7.


Prompt:
FEN: r1bq1rk1/ppp2np1/3p2Qp/4n3/1bB5/5N1P/PB3PP1/RN3RK1 w - -
Count each piece type for both sides.

Answer format: return exactly two lines starting "White counts:" and "Black counts:".

White counts: king=1; queen=1; rook=2; bishop=2; knight=2; pawn=4.
Black counts: king=1; queen=1; rook=2; bishop=2; knight=2; pawn=6.


Prompt:
FEN: rnbqkb1r/1pp1pp2/p6p/3pN1pn/3P3B/4P3/PPP2PPP/RN1QKB1R b KQkq -
Convert the piece counts into material value totals.

Answer format: return exactly two lines starting "White values:" and "Black values:".

White values: king=0; queen=9; rook=10; bishop=6; knight=6; pawn=8; total=39.
Black values: king=0; queen=9; rook=10; bishop=6; knight=6; pawn=8; total=39.


Prompt:
FEN: r4rk1/ppp1qpp1/2npbn1p/1Bb1p3/4P3/2PP1N1P/PP1N1PP1/R1BQR1K1 b - -
Trace inventory, counts, values, and material balance.

Answer format: return exactly four lines starting "Inventory:", "Counts:", "Values:", and "Balance:".

Inventory: white king=g1; queen=d1; rook=a1,e1; bishop=c1,b5; knight=d2,f3; pawn=a2,b2,f2,g2,c3,d3,h3,e4 | black king=g8; queen=e7; rook=a8,f8; bishop=c5,e6; knight=c6,f6; pawn=e5,d6,h6,a7,b7,c7,f7,g7
Counts: white king=1; queen=1; rook=2; bishop=2; knight=2; pawn=8 | black king=1; queen=1; rook=2; bishop=2; knight=2; pawn=8
Values: white total=39; black total=39
Balance: Material is equal.


Prompt:
Starting FEN: 2k2b2/5B2/p4p2/4pP2/8/3P4/PPK5/8 b - - 0 1
After the moves f8g7 f7b3, what is the resulting position?
State needed for full FEN:
Side to move: black
Castling rights: none
En passant: none
Halfmove clock: 0
Fullmove number: 1

Answer format: return exactly "Result FEN: <complete six-field FEN>".


Prompt:
Position (FEN): 2b5/4B3/8/k7/6N1/6PK/8/8 b - - 0 69
Show me the board.


Prompt:
Here is the current board:
8 . . . . . . . .
7 . . . . . . . .
6 R . . . . . P k
5 p P . . . . . P
4 P . . r . . . K
3 . . . . . . . .
2 . . . . . . . .
1 . . . . . . . .
  a b c d e f g h
Write the FEN for this position.
State needed for full FEN:
Side to move: white
Castling rights: none
En passant: none
Halfmove clock: 2
Fullmove number: 52

Answer format: return exactly one complete six-field FEN, with no prefix and no explanation.


Prompt:
FEN: r2qk2r/p1pn1ppp/1p1ppn2/8/2BPbB2/P1P2N2/2P2PPP/R2Q1RK1 w kq - 2 10
What piece is on f7?

Answer format: for a square query, return only the piece name or empty; do not include the square. For a locate query, return only space-separated squares.


Prompt:
FEN: r1b1Rqk1/p1p4p/2np1BpQ/8/2p2P2/8/PPP3PP/6K1 w - -
What is the material count for both sides?

White (10 pieces): 1 bishop, 1 king, 6 pawns, 1 queen, 1 rook. Black (11 pieces): 1 bishop, 1 king, 1 knight, 6 pawns, 1 queen, 1 rook. Black is up 3 point(s) of material.


Prompt:
FEN: r3r1k1/pp1q1p2/n1pp1bpp/P3p3/4P3/2PPNN1P/1PQ2PP1/3R1RK1 w - -
What is on e5?

Answer format: return exactly "<square>=<piece>" or "<square>=empty".


Prompt:
FEN: rnb1kbnr/ppp1pppp/8/6N1/8/2N4q/PPPPBP1P/R1BQK1R1 b Qkq -
What is the compressed FEN row for rank 3?

Answer format: return exactly "rank N: <compressed FEN row>".


Prompt:
FEN: r2q1rk1/p1p2pp1/5n1p/2b1n3/8/2PpBQ2/PP1N1PPP/R4RK1 w - - 4 15
For square c3, give the FEN row-from-top and file index.

Answer format: return exactly "<square>: file=<file>; rank=<rank>; fen_row_from_top=<1-8>; file_index=<1-8>".

c3: file=c; rank=3; fen_row_from_top=6; file_index=3


Prompt:
FEN: 8/8/8/4np2/k4N1P/6P1/5P2/6K1 w - - 1 54
Compressed rank 7 row: 8
Expand it into file cells a through h.

Answer format: return exactly "rank N: a=<cell>; b=<cell>; ...; h=<cell>".


Prompt:
Rank 4 row before: 4PB2
File g changes from 1 to b. Rewrite the compressed row.

Answer format: return exactly "rank N: <before-row> -> <after-row>".


Prompt:
Board FEN before: 8/6k1/R7/8/5P2/6KP/8/1r6
Apply square edits: g7 k->1; g8 1->k
Return the resulting board FEN only.

Answer format: return exactly "Result board FEN: <piece-placement-field>".

Result board FEN: 6k1/8/R7/8/5P2/6KP/8/1r6


Prompt:
Starting FEN: 8/pp6/3p1rkp/2p1pRn1/2P1P3/3PQ3/PP4P1/6K1 w - - 0 39
Move: b2b3
List the square lookups and rank edits.

Answer format: return exactly three lines starting "Lookup:", "Squares:", and "Ranks:"; do not include Result FEN.

Lookup: b2=white pawn; b3=empty.
Squares: b2 white pawn->empty; b3 empty->white pawn.
Ranks: rank 2 b P->1; rank 3 b 1->P.


Prompt:
Starting FEN: rn2kbnr/pb2q1pp/1ppp4/4P3/B7/2N2N2/PPP2PPP/R1BQK2R b KQkq - 0 10
Move: g7g6
Use square lookups and rank edits to assemble the resulting full FEN.
State needed for full FEN:
Side to move: black
Castling rights: KQkq
En passant: none
Halfmove clock: 0
Fullmove number: 10

Answer format: include the edit trace and exactly one final line "Result FEN: <complete six-field FEN>".

Move 1: black pawn g7g6.
Lookup: g7=black pawn; g6=empty.
Squares: g7 black pawn->empty; g6 empty->black pawn.
Ranks: rank 7 g p->1; rank 6 g 1->p.
Result FEN: rn2kbnr/pb2q2p/1ppp2p1/4P3/B7/2N2N2/PPP2PPP/R1BQK2R w KQkq - 0 11


Prompt:
Starting FEN: 5Nk1/R4bp1/2p2p2/3p3p/3P4/4P2P/5PP1/6K1 b - - 0 1
Move: g7g6
Rewrite the affected compressed FEN rank rows and give Result FEN.
State needed for full FEN:
Side to move: black
Castling rights: none
En passant: none
Halfmove clock: 0
Fullmove number: 1

Answer format: first line starts "Rows:" and final line is "Result FEN: <complete six-field FEN>".


Prompt:
Starting FEN: r1b2rk1/5ppp/p1p2n2/q7/8/2N1P3/PPP3PP/R2QK1NR b KQ - 0 13
After the moves a5g5, what is the resulting position?
State needed for full FEN:
Side to move: black
Castling rights: KQ
En passant: none
Halfmove clock: 0
Fullmove number: 13

Answer format: return exactly "Result FEN: <complete six-field FEN>".

Result FEN: r1b2rk1/5ppp/p1p2n2/6q1/8/2N1P3/PPP3PP/R2QK1NR w KQ - 1 14


Prompt:
FEN: rn3rk1/pp2ppbp/2pnb1p1/q7/3P1BP1/2N2N1P/PPP1BP2/R2QR1K1 w - -
List the material inventory by side and piece type.

Answer format: return exactly two lines starting "White inventory:" and "Black inventory:".

White inventory: king=g1; queen=d1; rook=a1,e1; bishop=e2,f4; knight=c3,f3; pawn=a2,b2,c2,f2,h3,d4,g4.
Black inventory: king=g8; queen=a5; rook=a8,f8; bishop=e6,g7; knight=d6,b8; pawn=c6,g6,a7,b7,e7,f7,h7.


Prompt:
FEN: r1bqk2r/pppp2pp/2n5/3BPp2/1b1Pn3/5N2/PP3PPP/RNBQK2R w KQkq -
Count each piece type for both sides.

Answer format: return exactly two lines starting "White counts:" and "Black counts:".

White counts: king=1; queen=1; rook=2; bishop=2; knight=2; pawn=7.
Black counts: king=1; queen=1; rook=2; bishop=2; knight=2; pawn=7.


Prompt:
FEN: 2n3k1/5pp1/2Q1b2p/b2p4/2pP2P1/2P1N3/p1B2PPK/r7 w - -
Convert the piece counts into material value totals.

Answer format: return exactly two lines starting "White values:" and "Black values:".

White values: king=0; queen=9; rook=0; bishop=3; knight=3; pawn=5; total=20.
Black values: king=0; queen=0; rook=5; bishop=6; knight=3; pawn=6; total=20.


Prompt:
FEN: 2R1B1k1/5p1p/p3p3/1p2N1p1/4q3/6P1/P3PPKP/8 w - -
Trace inventory, counts, values, and material balance.

Answer format: return exactly four lines starting "Inventory:", "Counts:", "Values:", and "Balance:".

Inventory: white king=g2; queen=none; rook=c8; bishop=e8; knight=e5; pawn=a2,e2,f2,h2,g3 | black king=g8; queen=e4; rook=none; bishop=none; knight=none; pawn=b5,g5,a6,e6,f7,h7
Counts: white king=1; queen=0; rook=1; bishop=1; knight=1; pawn=5 | black king=1; queen=1; rook=0; bishop=0; knight=0; pawn=6
Values: white total=16; black total=15
Balance: White is up 1 point(s) of material.


Prompt:
Starting FEN: b2r4/2Q2pkp/p4bp1/Np4q1/3P4/P2R1PPP/5K2/8 b - - 0 32
After the moves h7h6 d3b3, what is the resulting position?
State needed for full FEN:
Side to move: black
Castling rights: none
En passant: none
Halfmove clock: 0
Fullmove number: 32

Answer format: return exactly "Result FEN: <complete six-field FEN>".

Result FEN: b2r4/2Q2pk1/p4bpp/Np4q1/3P4/PR3PPP/5K2/8 b - - 1 33


Prompt:
Position (FEN): 8/8/p3b1p1/P6p/5P1P/3K2P1/1kp5/8 w - - 0 54
Show me the board.


Prompt:
Here is the current board:
8 r . b . r . k .
7 p p . . q p p .
6 . . p . . n . p
5 . . . p . . . .
4 . P . P n . . .
3 . . N B P N . .
2 P . Q . . P P P
1 . R . . . R K .
  a b c d e f g h
Write the FEN for this position.
State needed for full FEN:
Side to move: black
Castling rights: none
En passant: none
Halfmove clock: 0
Fullmove number: 1

Answer format: return exactly one complete six-field FEN, with no prefix and no explanation.


Prompt:
FEN: 8/8/6k1/R7/4K3/8/8/8 w - -
What piece is on a5?

Answer format: for a square query, return only the piece name or empty; do not include the square. For a locate query, return only space-separated squares.


Prompt:
FEN: 3r2k1/p4p2/1p2p1pp/8/7P/2Pq1Q2/PP3P2/1K4R1 w - -
What is the material count for both sides?

White (8 pieces): 1 king, 5 pawns, 1 queen, 1 rook. Black (9 pieces): 1 king, 6 pawns, 1 queen, 1 rook. Black is up 1 point(s) of material.


Prompt:
FEN: 3r2k1/5ppp/B3p3/Pp1r4/4NP2/2RP3P/5KP1/8 b - - 4 34
What is on h3?

Answer format: return exactly "<square>=<piece>" or "<square>=empty".


Prompt:
FEN: r1b1kbnr/1pp2ppp/p1n2q2/1B1p4/3P1P2/5N2/PPP3PP/RNBQK2R w KQkq - 0 7
What is the compressed FEN row for rank 6?

Answer format: return exactly "rank N: <compressed FEN row>".


Prompt:
FEN: 8/8/5k2/1B3p2/p4P2/P7/1P1K2P1/3b4 b - -
For square d2, give the FEN row-from-top and file index.

Answer format: return exactly "<square>: file=<file>; rank=<rank>; fen_row_from_top=<1-8>; file_index=<1-8>".

d2: file=d; rank=2; fen_row_from_top=7; file_index=4


Prompt:
FEN: r1bqk2r/pppn1pb1/3p1npp/4p3/3PP1PP/2N1B3/PPP1BP2/R2QK1NR w KQkq -
Compressed rank 6 row: 3p1npp
Expand it into file cells a through h.

Answer format: return exactly "rank N: a=<cell>; b=<cell>; ...; h=<cell>".


Prompt:
Rank 6 row before: 4p3
File c changes from 1 to q. Rewrite the compressed row.

Answer format: return exactly "rank N: <before-row> -> <after-row>".


2kr1bnr/pbppq1pp/1pn1pp2/8/1P1P4/P1P1PP2/3N2PP/R1BQKBNR w KQ - 0 8

Prompt:
Board FEN before: 2kr1bnr/pbppq1pp/1pn1pp2/8/1P1P4/P1P1PP2/3N2PP/R1BQKBNR
Apply square edits: g1 N->1; h3 1->N
Return the resulting board FEN only.

Answer format: return exactly "Result board FEN: <piece-placement-field>".

Result board FEN: 2kr1bnr/pbppq1pp/1pn1pp2/8/1P1P4/P1P1PP1N/3N2PP/R1BQKB1R


Prompt:
Starting FEN: 8/pp4pk/2p1p2p/2PpP1q1/3Pp3/4Pb2/PP2NQr1/5RK1 w - - 0 25
Move: g1h1
List the square lookups and rank edits.

Answer format: return exactly three lines starting "Lookup:", "Squares:", and "Ranks:"; do not include Result FEN.

Lookup: g1=white king; h1=empty.
Squares: g1 white king->empty; h1 empty->white king.
Ranks: rank 1 g K->1; rank 1 h 1->K.


Prompt:
Starting FEN: 7k/8/5K2/8/3N4/3B4/8/8 w - - 0 1
Move: d4f5
Use square lookups and rank edits to assemble the resulting full FEN.
State needed for full FEN:
Side to move: white
Castling rights: none
En passant: none
Halfmove clock: 0
Fullmove number: 1

Answer format: include the edit trace and exactly one final line "Result FEN: <complete six-field FEN>".

Move 1: white knight d4f5.
Lookup: d4=white knight; f5=empty.
Squares: d4 white knight->empty; f5 empty->white knight.
Ranks: rank 4 d N->1; rank 5 f 1->N.
Result FEN: 7k/8/5K2/5N2/8/3B4/8/8 b - - 1 1


Prompt:
Starting FEN: r3k1nr/ppp2ppp/2n5/2bBp1N1/4P3/3P4/PPP2PPP/RN1b1RK1 w kq - 0 9
Move: h2h3
Rewrite the affected compressed FEN rank rows and give Result FEN.
State needed for full FEN:
Side to move: white
Castling rights: kq
En passant: none
Halfmove clock: 0
Fullmove number: 9

Answer format: first line starts "Rows:" and final line is "Result FEN: <complete six-field FEN>".

Rows: rank 2 PPP2PPP->PPP2PP1; rank 3 3P4->3P3P.
Result FEN: r3k1nr/ppp2ppp/2n5/2bBp1N1/4P3/3P3P/PPP2PP1/RN1b1RK1 b kq - 0 9


Prompt:
Starting FEN: 3r1rk1/5ppp/Qp2p3/2pn4/P7/1qPP4/1P1R2PP/5R1K w - - 2 26
After the moves f1d1, what is the resulting position?
State needed for full FEN:
Side to move: white
Castling rights: none
En passant: none
Halfmove clock: 2
Fullmove number: 26

Answer format: return exactly "Result FEN: <complete six-field FEN>".

Result FEN: 3r1rk1/5ppp/Qp2p3/2pn4/P7/1qPP4/1P1R2PP/3R3K b - - 3 26


Prompt:
FEN: 8/5p2/6kp/8/6P1/5K2/8/8 b - -
List the material inventory by side and piece type.

Answer format: return exactly two lines starting "White inventory:" and "Black inventory:".

White inventory: king=f3; queen=none; rook=none; bishop=none; knight=none; pawn=g4.
Black inventory: king=g6; queen=none; rook=none; bishop=none; knight=none; pawn=h6,f7.


Prompt:
FEN: 1r4k1/5p1p/4ppq1/8/8/4PQP1/5PK1/R7 b - -
Count each piece type for both sides.

Answer format: return exactly two lines starting "White counts:" and "Black counts:".

White counts: king=1; queen=1; rook=1; bishop=0; knight=0; pawn=3.
Black counts: king=1; queen=1; rook=1; bishop=0; knight=0; pawn=4.


Prompt:
FEN: r2qkb1r/1b1n2p1/p3ppPp/3n4/Np1Np2P/4BP1B/PPPQ4/2KR3R w kq -
Convert the piece counts into material value totals.

Answer format: return exactly two lines starting "White values:" and "Black values:".

White values: king=0; queen=9; rook=10; bishop=6; knight=6; pawn=6; total=37.
Black values: king=0; queen=9; rook=10; bishop=6; knight=6; pawn=7; total=38.


Prompt:
FEN: 8/8/8/8/2K5/8/k1B5/2B5 w - -
Trace inventory, counts, values, and material balance.

Answer format: return exactly four lines starting "Inventory:", "Counts:", "Values:", and "Balance:".

Inventory: white king=c4; queen=none; rook=none; bishop=c1,c2; knight=none; pawn=none | black king=a2; queen=none; rook=none; bishop=none; knight=none; pawn=none
Counts: white king=1; queen=0; rook=0; bishop=2; knight=0; pawn=0 | black king=1; queen=0; rook=0; bishop=0; knight=0; pawn=0
Values: white total=6; black total=0
Balance: White is up 6 point(s) of material.


Prompt:
Starting FEN: rn2kb1r/pp2qp1p/2ppb1p1/8/8/B1P1N3/P1PPQPPP/1R2KB1R b Kkq - 0 1
After the moves b8d7 b1c1, what is the resulting position?
State needed for full FEN:
Side to move: black
Castling rights: Kkq
En passant: none
Halfmove clock: 0
Fullmove number: 1

Answer format: return exactly "Result FEN: <complete six-field FEN>".

Result FEN: r3kb1r/pp1nqp1p/2ppb1p1/8/8/B1P1N3/P1PPQPPP/2R1KB1R b Kkq - 2 2


Prompt:
Position (FEN): rn1qk1nr/pp2ppbp/2p3p1/3p4/2PP2b1/3BPN1P/PP3PP1/RNBQK2R b KQkq -
Show me the board.

8 r n . q k . n r
7 p p . . p p b p
6 . . p . . . p .
5 . . . p . . . .
4 . . P P . . b .
3 . . . B P N . P
2 P P . . . P P .
1 R N B Q K . . R
  a b c d e f g h


Prompt:
Here is the current board:
8 . . . r r . k .
7 . b . . . p p p
6 p . n . . . . .
5 . p . . . . . .
4 . . p . . . . .
3 q . P . K N . .
2 B . P . Q P P P
1 . . . R . . . R
  a b c d e f g h
Write the FEN for this position.
State needed for full FEN:
Side to move: white
Castling rights: none
En passant: none
Halfmove clock: 4
Fullmove number: 22

Answer format: return exactly one complete six-field FEN, with no prefix and no explanation.


Prompt:
FEN: r4rk1/pp4pp/4p3/q1pp4/8/2b2P2/P1P3PP/1KBRQB1R w - -
What piece is on a7?

Answer format: for a square query, return only the piece name or empty; do not include the square. For a locate query, return only space-separated squares.


Prompt:
FEN: rnbq2k1/pppp1ppp/5n2/6B1/2N1r3/2P5/PPP2PPP/R2QKB1R w KQ -
What is the material count for both sides?

White (14 pieces): 2 bishops, 1 king, 1 knight, 7 pawns, 1 queen, 2 rooks. Black (14 pieces): 1 bishop, 1 king, 2 knights, 7 pawns, 1 queen, 2 rooks. Material is equal.


Prompt:
FEN: 1Q6/2P5/6k1/3Q4/6p1/6K1/7P/8 w - -
What is on g4?

Answer format: return exactly "<square>=<piece>" or "<square>=empty".


Prompt:
FEN: 8/2p2p2/1p4kp/6p1/1P6/P5P1/1B2KP1r/3R4 w - - 4 37
What is the compressed FEN row for rank 5?

Answer format: return exactly "rank N: <compressed FEN row>".


Prompt:
FEN: r1bq1rk1/ppp1bppp/2np1n2/4p3/3P4/2NQ1N1P/PPP1BPP1/R1B2RK1 w - - 4 9
For square c2, give the FEN row-from-top and file index.

Answer format: return exactly "<square>: file=<file>; rank=<rank>; fen_row_from_top=<1-8>; file_index=<1-8>".

c2: file=c; rank=2; fen_row_from_top=7; file_index=3


Prompt:
FEN: 8/2k5/8/8/1PP4R/4K3/3r3P/8 b - - 9 53
Compressed rank 6 row: 8
Expand it into file cells a through h.

Answer format: return exactly "rank N: a=<cell>; b=<cell>; ...; h=<cell>".


r1bqkbnr/ppp2ppp/2np4/8/2BNP3/8/PPP2PPP/RNBQK2R b KQkq - 0 5

Prompt:
Rank 7 row before: ppp2ppp
File f changes from p to 1. Rewrite the compressed row.

Answer format: return exactly "rank N: <before-row> -> <after-row>".


Prompt:
Board FEN before: r1b1k2r/pp3ppp/3p4/2p1p1B1/4P3/3P4/PPPKnP1P/3R3R
Apply square edits: c8 b->1; g4 1->b
Return the resulting board FEN only.

Answer format: return exactly "Result board FEN: <piece-placement-field>".

Result board FEN: r3k2r/pp3ppp/3p4/2p1p1B1/4P1b1/3P4/PPPKnP1P/3R3R


Prompt:
Starting FEN: 2r2r1k/pb5p/1p2Q1p1/2pp2q1/8/PP1BP3/2P3PP/4RRK1 w - -
Move: e6d6
List the square lookups and rank edits.

Answer format: return exactly three lines starting "Lookup:", "Squares:", and "Ranks:"; do not include Result FEN.

Lookup: e6=white queen; d6=empty.
Squares: e6 white queen->empty; d6 empty->white queen.
Ranks: rank 6 e Q->1; rank 6 d 1->Q.


Prompt:
Starting FEN: 1r3rk1/5pp1/p2b1n1p/3Pq3/P7/3P1Q1P/5PP1/R1RB2K1 w - - 8 29
Move: f3f4
Use square lookups and rank edits to assemble the resulting full FEN.
State needed for full FEN:
Side to move: white
Castling rights: none
En passant: none
Halfmove clock: 8
Fullmove number: 29

Answer format: include the edit trace and exactly one final line "Result FEN: <complete six-field FEN>".

Move 1: white queen f3f4.
Lookup: f3=white queen; f4=empty.
Squares: f3 white queen->empty; f4 empty->white queen.
Ranks: rank 3 f Q->1; rank 4 f 1->Q.
Result FEN: 1r3rk1/5pp1/p2b1n1p/3Pq3/P4Q2/3P3P/5PP1/R1RB2K1 b - - 9 29


Prompt:
Starting FEN: 8/8/p3bk2/1p3pp1/3K4/6P1/8/8 w - - 2 46
Move: d4c5
Rewrite the affected compressed FEN rank rows and give Result FEN.
State needed for full FEN:
Side to move: white
Castling rights: none
En passant: none
Halfmove clock: 2
Fullmove number: 46

Answer format: first line starts "Rows:" and final line is "Result FEN: <complete six-field FEN>".


Prompt:
Starting FEN: r1bqkb1r/pp2pppp/2np1n2/2p5/2B1P3/3P1N2/PPP2PPP/RNBQK2R w KQkq - 1 5
After the moves f3g5, what is the resulting position?
State needed for full FEN:
Side to move: white
Castling rights: KQkq
En passant: none
Halfmove clock: 1
Fullmove number: 5

Answer format: return exactly "Result FEN: <complete six-field FEN>".

Result FEN: r1bqkb1r/pp2pppp/2np1n2/2p3N1/2B1P3/3P4/PPP2PPP/RNBQK2R b KQkq - 2 5


Prompt:
FEN: r2qkbnr/1pp1pppp/3pb3/1P2n3/8/1QN5/P2PPPPP/R1B1KBNR w KQkq - 1 8
List the material inventory by side and piece type.

Answer format: return exactly two lines starting "White inventory:" and "Black inventory:".

White inventory: king=e1; queen=b3; rook=a1,h1; bishop=c1,f1; knight=g1,c3; pawn=a2,d2,e2,f2,g2,h2,b5.
Black inventory: king=e8; queen=d8; rook=a8,h8; bishop=e6,f8; knight=e5,g8; pawn=d6,b7,c7,e7,f7,g7,h7.


Prompt:
FEN: rnbqkbnr/ppp2ppp/8/4P3/3pP3/5Q2/PPP2PPP/RNB1KBNR b KQkq - 1 4
Count each piece type for both sides.

Answer format: return exactly two lines starting "White counts:" and "Black counts:".

White counts: king=1; queen=1; rook=2; bishop=2; knight=2; pawn=8.
Black counts: king=1; queen=1; rook=2; bishop=2; knight=2; pawn=7.


Prompt:
FEN: rnb1k2r/ppq2ppp/2pb1n2/4p3/1P2N3/P2BPN2/1B1P1PPP/R2Q1RK1 b kq - 1 11
Convert the piece counts into material value totals.

Answer format: return exactly two lines starting "White values:" and "Black values:".

White values: king=0; queen=9; rook=10; bishop=6; knight=6; pawn=7; total=38.
Black values: king=0; queen=9; rook=10; bishop=6; knight=6; pawn=7; total=38.


Prompt:
FEN: 1r2k2r/pB1n1p1p/5p2/1Qp5/3p1b2/6P1/4PP1P/5RK1 w k -
Trace inventory, counts, values, and material balance.

Answer format: return exactly four lines starting "Inventory:", "Counts:", "Values:", and "Balance:".

Inventory: white king=g1; queen=b5; rook=f1; bishop=b7; knight=none; pawn=e2,f2,h2,g3 | black king=e8; queen=none; rook=b8,h8; bishop=f4; knight=d7; pawn=d4,c5,f6,a7,f7,h7
Counts: white king=1; queen=1; rook=1; bishop=1; knight=0; pawn=4 | black king=1; queen=0; rook=2; bishop=1; knight=1; pawn=6
Values: white total=21; black total=22
Balance: Black is up 1 point(s) of material.


Prompt:
Starting FEN: rn1qkbnr/1pp3pp/p3pp2/2Pp1b2/3P1B2/4PN2/PP3PPP/RN1QKB1R b KQkq - 0 1
After the moves f5b1 d1b3, what is the resulting position?
State needed for full FEN:
Side to move: black
Castling rights: KQkq
En passant: none
Halfmove clock: 0
Fullmove number: 1

Answer format: return exactly "Result FEN: <complete six-field FEN>".

Result FEN: rn1qkbnr/1pp3pp/p3pp2/2Pp4/3P1B2/1Q2PN2/PP3PPP/Rb2KB1R b KQkq - 1 2


Prompt:
Position (FEN): 7r/p4pk1/4p2p/4P3/1bN5/4BP2/4K1P1/2R5 w - -
Show me the board.


Prompt:
Here is the current board:
8 . . . . . . . .
7 . p . . . . . .
6 . . . . . . . .
5 . . . . . . . .
4 . . . . R . . .
3 . . . k . . . .
2 . . . . p K . .
1 . . . . . . . .
  a b c d e f g h
Write the FEN for this position.
State needed for full FEN:
Side to move: black
Castling rights: none
En passant: none
Halfmove clock: 0
Fullmove number: 50

Answer format: return exactly one complete six-field FEN, with no prefix and no explanation.


Prompt:
FEN: 3r1r1k/pp4p1/2n4p/2pP1b2/2Q5/3BP3/PPN3qP/R2K1R2 b - - 1 19
What piece is on d8?

Answer format: for a square query, return only the piece name or empty; do not include the square. For a locate query, return only space-separated squares.


Prompt:
FEN: r5r1/2p1k3/p2p1b1p/3QP3/P1P4q/4PR2/1P6/R5K1 w - - 1 28
What is the material count for both sides?

White (9 pieces): 1 king, 5 pawns, 1 queen, 2 rooks. Black (9 pieces): 1 bishop, 1 king, 4 pawns, 1 queen, 2 rooks. Black is up 2 point(s) of material.


Prompt:
FEN: 8/8/1k2B3/1N6/1K6/8/8/8 w - -
What is on e6?

Answer format: return exactly "<square>=<piece>" or "<square>=empty".


Prompt:
FEN: 1B5k/1pp3p1/5p1p/3P4/1P2b1r1/P1P5/6BP/6K1 w - - 2 32
What is the compressed FEN row for rank 3?

Answer format: return exactly "rank N: <compressed FEN row>".


Prompt:
FEN: rn3rk1/3bppbp/p2p1np1/2pP4/4P3/1PN5/1P1N1PPP/R1B1KB1R w KQ -
For square f8, give the FEN row-from-top and file index.

Answer format: return exactly "<square>: file=<file>; rank=<rank>; fen_row_from_top=<1-8>; file_index=<1-8>".

f8: file=f; rank=8; fen_row_from_top=1; file_index=6


Prompt:
FEN: rn1qkbnr/ppp2pp1/4p2p/3p1b2/8/1P1P1N2/PBP1PPPP/RN1QKB1R w KQkq -
Compressed rank 3 row: 1P1P1N2
Expand it into file cells a through h.

Answer format: return exactly "rank N: a=<cell>; b=<cell>; ...; h=<cell>".


r1b2rk1/ppp2pbp/5np1/2q5/4PB2/2NB4/PPP3PP/R2Q1R1K w - -

Prompt:
Rank 1 row before: R2Q1R1K
File d changes from Q to 1. Rewrite the compressed row.

Answer format: return exactly "rank N: <before-row> -> <after-row>".


Prompt:
Board FEN before: rn6/1p1kq1p1/p2p1nQ1/2pPpP2/2P3P1/8/PP2N3/R4RK1
Apply square edits: a1 R->1; c1 1->R
Return the resulting board FEN only.

Answer format: return exactly "Result board FEN: <piece-placement-field>".

Result board FEN: rn6/1p1kq1p1/p2p1nQ1/2pPpP2/2P3P1/8/PP2N3/2R2RK1


Prompt:
Starting FEN: 2k5/3R4/1PB5/P7/6p1/6P1/5PK1/8 w - -
Move: d7d3
List the square lookups and rank edits.

Answer format: return exactly three lines starting "Lookup:", "Squares:", and "Ranks:"; do not include Result FEN.

Lookup: d7=white rook; d3=empty.
Squares: d7 white rook->empty; d3 empty->white rook.
Ranks: rank 7 d R->1; rank 3 d 1->R.


Prompt:
Starting FEN: r1b1k2r/pp1p1ppp/n4n2/8/1b6/6Q1/PPqPNPPP/RNB1KB1R w KQkq - 0 8
Move: h1g1
Use square lookups and rank edits to assemble the resulting full FEN.
State needed for full FEN:
Side to move: white
Castling rights: KQkq
En passant: none
Halfmove clock: 0
Fullmove number: 8

Answer format: include the edit trace and exactly one final line "Result FEN: <complete six-field FEN>".

Move 1: white rook h1g1.
Lookup: h1=white rook; g1=empty.
Squares: h1 white rook->empty; g1 empty->white rook.
Ranks: rank 1 h R->1; rank 1 g 1->R.
Result FEN: r1b1k2r/pp1p1ppp/n4n2/8/1b6/6Q1/PPqPNPPP/RNB1KBR1 b Qkq - 1 8


Prompt:
Starting FEN: k2r4/pp5p/4R3/2p5/8/7P/5PP1/6K1 w - - 0 31
Move: e6b6
Rewrite the affected compressed FEN rank rows and give Result FEN.
State needed for full FEN:
Side to move: white
Castling rights: none
En passant: none
Halfmove clock: 0
Fullmove number: 31

Answer format: first line starts "Rows:" and final line is "Result FEN: <complete six-field FEN>".


Prompt:
Starting FEN: r1bqk2r/pp2bpp1/2np1n1p/1Bp1p3/4P3/2P2N1P/PP1P1PP1/RNBQ1RK1 w kq - 0 1
After the moves d1e1, what is the resulting position?
State needed for full FEN:
Side to move: white
Castling rights: kq
En passant: none
Halfmove clock: 0
Fullmove number: 1

Answer format: return exactly "Result FEN: <complete six-field FEN>".

Result FEN: r1bqk2r/pp2bpp1/2np1n1p/1Bp1p3/4P3/2P2N1P/PP1P1PP1/RNB1QRK1 b kq - 1 1


Prompt:
FEN: 1R6/1p3k2/p1b5/P1P5/4r3/8/1K4pp/8 w - - 0 49
List the material inventory by side and piece type.

Answer format: return exactly two lines starting "White inventory:" and "Black inventory:".

White inventory: king=b2; queen=none; rook=b8; bishop=none; knight=none; pawn=a5,c5.
Black inventory: king=f7; queen=none; rook=e4; bishop=c6; knight=none; pawn=g2,h2,a6,b7.


Prompt:
FEN: 8/8/1p4p1/1P1p3p/1P1Pp2k/8/5K2/8 w - - 0 51
Count each piece type for both sides.

Answer format: return exactly two lines starting "White counts:" and "Black counts:".

White counts: king=1; queen=0; rook=0; bishop=0; knight=0; pawn=3.
Black counts: king=1; queen=0; rook=0; bishop=0; knight=0; pawn=5.


Prompt:
FEN: b6r/2kn3p/2pq4/1p1p1Q2/4pP2/1PN3P1/2PP1P1P/2B2RK1 w - - 1 21
Convert the piece counts into material value totals.

Answer format: return exactly two lines starting "White values:" and "Black values:".

White values: king=0; queen=9; rook=5; bishop=3; knight=3; pawn=7; total=27.
Black values: king=0; queen=9; rook=5; bishop=3; knight=3; pawn=5; total=25.


Prompt:
FEN: r6r/p3bkpp/npp1bpn1/8/5p2/P1N2N2/1BPP2PP/R3K2R w - -
Trace inventory, counts, values, and material balance.

Answer format: return exactly four lines starting "Inventory:", "Counts:", "Values:", and "Balance:".

Inventory: white king=e1; queen=none; rook=a1,h1; bishop=b2; knight=c3,f3; pawn=c2,d2,g2,h2,a3 | black king=f7; queen=none; rook=a8,h8; bishop=e6,e7; knight=a6,g6; pawn=f4,b6,c6,f6,a7,g7,h7
Counts: white king=1; queen=0; rook=2; bishop=1; knight=2; pawn=5 | black king=1; queen=0; rook=2; bishop=2; knight=2; pawn=7
Values: white total=24; black total=29
Balance: Black is up 5 point(s) of material.


Prompt:
Starting FEN: 8/1k6/2R5/1K6/7r/P7/1P6/8 w - - 17 59
After the moves b5c5 h4g4 c6a6, what is the resulting position?
State needed for full FEN:
Side to move: white
Castling rights: none
En passant: none
Halfmove clock: 17
Fullmove number: 59

Answer format: return exactly "Result FEN: <complete six-field FEN>".


Prompt:
Position (FEN): 6k1/Q4pp1/5n1p/3N4/1rq1P3/7P/6P1/R4R1K b - - 1 38
Show me the board.


Prompt:
Here is the current board:
8 r . . . k . . r
7 p p . . . p p p
6 . q . . . n . .
5 . . b p . . . .
4 . n . . . . b .
3 . N N Q B . P .
2 P P P . . P B P
1 R . . . K . . R
  a b c d e f g h
Write the FEN for this position.
State needed for full FEN:
Side to move: white
Castling rights: KQkq
En passant: none
Halfmove clock: 0
Fullmove number: 1

Answer format: return exactly one complete six-field FEN, with no prefix and no explanation.

r3k2r/pp3ppp/1q3n2/2bp4/1n4b1/1NNQB1P1/PPP2PBP/R3K2R w KQkq - 0 1


Prompt:
FEN: 2k2r2/pbpp4/1p2p2P/4Pn2/2P1NR1n/1P1B3P/P2r4/R6K b - - 1 24
What piece is on c4?

Answer format: for a square query, return only the piece name or empty; do not include the square. For a locate query, return only space-separated squares.


Prompt:
FEN: 8/2p3pp/2p5/p3p3/2k1K1P1/P7/7P/8 w - - 0 29
What is the material count for both sides?

White (4 pieces): 1 king, 3 pawns. Black (7 pieces): 1 king, 6 pawns. Black is up 3 point(s) of material.


Prompt:
FEN: 8/p1p2p2/5k2/8/2PnB1r1/P4PPp/1P5P/5RK1 b - - 0 32
What is on f7?

Answer format: return exactly "<square>=<piece>" or "<square>=empty".


Prompt:
FEN: r3kb1r/pp2pppp/1qnp1n2/5b2/3P1B2/2N1P3/PPQ2PPP/R3KBNR w KQkq -
What is the compressed FEN row for rank 4?

Answer format: return exactly "rank N: <compressed FEN row>".


Prompt:
FEN: rnbqkb1r/p4p1p/2pp1pp1/6B1/3P4/2Q5/PPP2PPP/2KR1BNR w kq -
For square a7, give the FEN row-from-top and file index.

Answer format: return exactly "<square>: file=<file>; rank=<rank>; fen_row_from_top=<1-8>; file_index=<1-8>".

a7: file=a; rank=7; fen_row_from_top=2; file_index=1


Prompt:
FEN: rnbq1rk1/ppp2pbp/3p1np1/4p3/3PPP2/2PB4/PP2N1PP/RNBQ1RK1 b - -
Compressed rank 8 row: rnbq1rk1
Expand it into file cells a through h.

Answer format: return exactly "rank N: a=<cell>; b=<cell>; ...; h=<cell>".


Prompt:
Rank 4 row before: 3p4
File f changes from 1 to p. Rewrite the compressed row.

Answer format: return exactly "rank N: <before-row> -> <after-row>".


r1b1kb1r/p1qn1ppp/2p1pn2/1p6/2BP4/2N2N2/PPPBQPPP/2KR3R w kq -

Prompt:
Board FEN before: r1b1kb1r/p1qn1ppp/2p1pn2/1p6/2BP4/2N2N2/PPPBQPPP/2KR3R
Apply square edits: d2 B->1; f4 1->B
Return the resulting board FEN only.

Answer format: return exactly "Result board FEN: <piece-placement-field>".

Result board FEN: r1b1kb1r/p1qn1ppp/2p1pn2/1p6/2BP1B2/2N2N2/PPP1QPPP/2KR3R


Prompt:
Starting FEN: 1r3rk1/1b3ppp/p1n1pb2/8/1PB5/P4N1P/R4PP1/3R2K1 b - - 0 19
Move: h7h6
List the square lookups and rank edits.

Answer format: return exactly three lines starting "Lookup:", "Squares:", and "Ranks:"; do not include Result FEN.

Lookup: h7=black pawn; h6=empty.
Squares: h7 black pawn->empty; h6 empty->black pawn.
Ranks: rank 7 h p->1; rank 6 h 1->p.


Prompt:
Starting FEN: 8/2p4k/6p1/P6p/4Q3/8/1PP5/1K3q2 w - - 1 37
Move: b1a2
Use square lookups and rank edits to assemble the resulting full FEN.
State needed for full FEN:
Side to move: white
Castling rights: none
En passant: none
Halfmove clock: 1
Fullmove number: 37

Answer format: include the edit trace and exactly one final line "Result FEN: <complete six-field FEN>".

Move 1: white king b1a2.
Lookup: b1=white king; a2=empty.
Squares: b1 white king->empty; a2 empty->white king.
Ranks: rank 1 b K->1; rank 2 a 1->K.
Result FEN: 8/2p4k/6p1/P6p/4Q3/8/KPP5/5q2 b - - 2 37


Prompt:
Starting FEN: 8/8/2k5/Q4K2/8/8/8/7R w - - 0 1
Move: a5b6
Rewrite the affected compressed FEN rank rows and give Result FEN.
State needed for full FEN:
Side to move: white
Castling rights: none
En passant: none
Halfmove clock: 0
Fullmove number: 1

Answer format: first line starts "Rows:" and final line is "Result FEN: <complete six-field FEN>".


Prompt:
Starting FEN: rn2kbnr/pbppqppp/1p2p3/8/3PPP2/2NB4/PPP3PP/R1BQK1NR b KQkq - 0 5
After the moves b7d5, what is the resulting position?
State needed for full FEN:
Side to move: black
Castling rights: KQkq
En passant: none
Halfmove clock: 0
Fullmove number: 5

Answer format: return exactly "Result FEN: <complete six-field FEN>".

Result FEN: rn2kbnr/p1ppqppp/1p2p3/3b4/3PPP2/2NB4/PPP3PP/R1BQK1NR w KQkq - 1 6


Prompt:
FEN: 4rr1k/1b1q1p2/p1n3Q1/1p5p/3p1B2/PB1P3P/1PP3P1/R3R1K1 w - - 1 21
List the material inventory by side and piece type.

Answer format: return exactly two lines starting "White inventory:" and "Black inventory:".

White inventory: king=g1; queen=g6; rook=a1,e1; bishop=b3,f4; knight=none; pawn=b2,c2,g2,a3,d3,h3.
Black inventory: king=h8; queen=d7; rook=e8,f8; bishop=b7; knight=c6; pawn=d4,b5,h5,a6,f7.


Prompt:
FEN: rn1qkb1r/pp3ppp/2p1pnb1/3p4/3P1B1P/2NBPN2/PPP2PP1/R2QK2R b KQkq -
Count each piece type for both sides.

Answer format: return exactly two lines starting "White counts:" and "Black counts:".

White counts: king=1; queen=1; rook=2; bishop=2; knight=2; pawn=8.
Black counts: king=1; queen=1; rook=2; bishop=2; knight=2; pawn=8.


Prompt:
FEN: 1k5r/ppp5/2n2p1p/5B2/1b6/5P1N/1q1pQKPP/R6R b - - 2 27
Convert the piece counts into material value totals.

Answer format: return exactly two lines starting "White values:" and "Black values:".

White values: king=0; queen=9; rook=10; bishop=3; knight=3; pawn=3; total=28.
Black values: king=0; queen=9; rook=5; bishop=3; knight=3; pawn=6; total=26.


Prompt:
FEN: r1b3k1/1p3pp1/p2b4/2r4p/2N2N2/2P3PP/P4P2/R4K1R w - - 1 24
Trace inventory, counts, values, and material balance.

Answer format: return exactly four lines starting "Inventory:", "Counts:", "Values:", and "Balance:".

Inventory: white king=f1; queen=none; rook=a1,h1; bishop=none; knight=c4,f4; pawn=a2,f2,c3,g3,h3 | black king=g8; queen=none; rook=c5,a8; bishop=d6,c8; knight=none; pawn=h5,a6,b7,f7,g7
Counts: white king=1; queen=0; rook=2; bishop=0; knight=2; pawn=5 | black king=1; queen=0; rook=2; bishop=2; knight=0; pawn=5
Values: white total=21; black total=21
Balance: Material is equal.


Prompt:
Starting FEN: 8/4n1p1/4k2p/p2np3/2B5/PN4P1/1P2KP1P/8 w - - 6 36
After the moves h2h4 e6f6, what is the resulting position?
State needed for full FEN:
Side to move: white
Castling rights: none
En passant: none
Halfmove clock: 6
Fullmove number: 36

Answer format: return exactly "Result FEN: <complete six-field FEN>".


Prompt:
Position (FEN): rnbq1rk1/ppp2pp1/3bpn1p/3p4/3P1B2/2NBPQ1N/PPP2PPP/R3K2R b KQ -
Show me the board.

8 r n b q . r k .
7 p p p . . p p .
6 . . . b p n . p
5 . . . p . . . .
4 . . . P . B . .
3 . . N B P Q . N
2 P P P . . P P P
1 R . . . K . . R
  a b c d e f g h


Prompt:
Here is the current board:
8 . . . . . n k .
7 . . . . . . p .
6 . Q . . p q . p
5 . . . . . . . .
4 . . . . B . . .
3 . . . . P . P .
2 . . . . . P . P
1 . . . . . . K .
  a b c d e f g h
Write the FEN for this position.
State needed for full FEN:
Side to move: white
Castling rights: none
En passant: none
Halfmove clock: 0
Fullmove number: 1

Answer format: return exactly one complete six-field FEN, with no prefix and no explanation.


Prompt:
FEN: rn2k2r/2p1qpp1/1p2p2p/p1bN4/8/P2P1Q1N/1PP2PPP/R1BR2K1 b kq - 0 12
What piece is on f3?

Answer format: for a square query, return only the piece name or empty; do not include the square. For a locate query, return only space-separated squares.


Prompt:
FEN: 3qk2r/1pp3pp/1pn1bp2/4p3/4PP2/r1PP2P1/P3N1BP/R2Q1RK1 b k - 0 13
What is the material count for both sides?

White (13 pieces): 1 bishop, 1 king, 1 knight, 7 pawns, 1 queen, 2 rooks. Black (13 pieces): 1 bishop, 1 king, 1 knight, 7 pawns, 1 queen, 2 rooks. Material is equal.


Prompt:
FEN: 2kr4/pq1n4/4pr2/1pp5/2p3Q1/2N3P1/PP3P1P/R3R1K1 b - -
What is on d2?

Answer format: return exactly "<square>=<piece>" or "<square>=empty".


Prompt:
FEN: 8/8/pr3k2/4p3/4K3/8/P2R1P2/8 w - - 7 37
What is the compressed FEN row for rank 2?

Answer format: return exactly "rank N: <compressed FEN row>".


Prompt:
FEN: rnbq1rk1/p3ppbp/2p2np1/8/3PpP2/7N/PPP2BPP/RN1QK2R w KQ - 2 9
For square b8, give the FEN row-from-top and file index.

Answer format: return exactly "<square>: file=<file>; rank=<rank>; fen_row_from_top=<1-8>; file_index=<1-8>".

b8: file=b; rank=8; fen_row_from_top=1; file_index=2


Prompt:
FEN: r1bq1r2/ppppbkpp/2n1N3/8/3P4/2P5/P1P3PP/R1BQ1RK1 b - -
Compressed rank 3 row: 2P5
Expand it into file cells a through h.

Answer format: return exactly "rank N: a=<cell>; b=<cell>; ...; h=<cell>".


Prompt:
Rank 1 row before: R5K1
File f changes from 1 to K. Rewrite the compressed row.

Answer format: return exactly "rank N: <before-row> -> <after-row>".


Prompt:
Board FEN before: 8/8/8/1k1b4/8/R7/6p1/4b1K1
Apply square edits: e1 b->1; a5 1->b
Return the resulting board FEN only.

Answer format: return exactly "Result board FEN: <piece-placement-field>".

Result board FEN: 8/8/8/bk1b4/8/R7/6p1/6K1


Prompt:
Starting FEN: 1r3rk1/pb1pnppp/2nN1q2/2p1p3/4P3/3Q1B2/PPP2PPP/R1B2RK1 w - - 4 14
Move: f3e2
List the square lookups and rank edits.

Answer format: return exactly three lines starting "Lookup:", "Squares:", and "Ranks:"; do not include Result FEN.

Lookup: f3=white bishop; e2=empty.
Squares: f3 white bishop->empty; e2 empty->white bishop.
Ranks: rank 3 f B->1; rank 2 e 1->B.


Prompt:
Starting FEN: r3kbnr/1ppb1ppp/p7/n2NP3/P1p2P2/8/1P1BP1PP/R2K1BNR b kq - 0 1
Move: c7c6
Use square lookups and rank edits to assemble the resulting full FEN.
State needed for full FEN:
Side to move: black
Castling rights: kq
En passant: none
Halfmove clock: 0
Fullmove number: 1

Answer format: include the edit trace and exactly one final line "Result FEN: <complete six-field FEN>".

Move 1: black pawn c7c6.
Lookup: c7=black pawn; c6=empty.
Squares: c7 black pawn->empty; c6 empty->black pawn.
Ranks: rank 7 c p->1; rank 6 c 1->p.
Result FEN: r3kbnr/1p1b1ppp/p1p5/n2NP3/P1p2P2/8/1P1BP1PP/R2K1BNR w kq - 0 2


Prompt:
Starting FEN: r2q1rk1/ppp1bp1p/2n1b2p/3pp3/3PPnP1/2P2N1P/PP3P1Q/RN2KB1R b KQ - 0 12
Move: d8b8
Rewrite the affected compressed FEN rank rows and give Result FEN.
State needed for full FEN:
Side to move: black
Castling rights: KQ
En passant: none
Halfmove clock: 0
Fullmove number: 12

Answer format: first line starts "Rows:" and final line is "Result FEN: <complete six-field FEN>".

Rows: rank 8 r2q1rk1->rq3rk1.
Result FEN: rq3rk1/ppp1bp1p/2n1b2p/3pp3/3PPnP1/2P2N1P/PP3P1Q/RN2KB1R w KQ - 1 13


Prompt:
Starting FEN: r3r1k1/5p1p/1R1p2pb/p7/2p3K1/8/P4PPP/7R b - - 1 26
After the moves d6d5, what is the resulting position?
State needed for full FEN:
Side to move: black
Castling rights: none
En passant: none
Halfmove clock: 1
Fullmove number: 26

Answer format: return exactly "Result FEN: <complete six-field FEN>".


Prompt:
FEN: r2q1rk1/pppb1pb1/n3p1pp/3pPn2/2PP4/1B3Q1N/PP3PPP/RNB2RK1 b - - 0 11
List the material inventory by side and piece type.

Answer format: return exactly two lines starting "White inventory:" and "Black inventory:".

White inventory: king=g1; queen=f3; rook=a1,f1; bishop=c1,b3; knight=b1,h3; pawn=a2,b2,f2,g2,h2,c4,d4,e5.
Black inventory: king=g8; queen=d8; rook=a8,f8; bishop=d7,g7; knight=f5,a6; pawn=d5,e6,g6,h6,a7,b7,c7,f7.


Prompt:
FEN: r4rk1/pp3p1p/2n2bp1/5b2/2N5/4P2P/PP2BPP1/R1BqR1K1 w - - 0 17
Count each piece type for both sides.

Answer format: return exactly two lines starting "White counts:" and "Black counts:".

White counts: king=1; queen=0; rook=2; bishop=2; knight=1; pawn=6.
Black counts: king=1; queen=1; rook=2; bishop=2; knight=1; pawn=5.


Prompt:
FEN: 1k6/8/2K5/2Q5/8/8/8/5B2 w - -
Convert the piece counts into material value totals.

Answer format: return exactly two lines starting "White values:" and "Black values:".

White values: king=0; queen=9; rook=0; bishop=3; knight=0; pawn=0; total=12.
Black values: king=0; queen=0; rook=0; bishop=0; knight=0; pawn=0; total=0.


Prompt:
FEN: r2qkb1r/pb4pp/4p3/1Pp1n2Q/3pN3/7P/PP3PP1/R1B1KB1R b KQkq -
Trace inventory, counts, values, and material balance.

Answer format: return exactly four lines starting "Inventory:", "Counts:", "Values:", and "Balance:".

Inventory: white king=e1; queen=h5; rook=a1,h1; bishop=c1,f1; knight=e4; pawn=a2,b2,f2,g2,h3,b5 | black king=e8; queen=d8; rook=a8,h8; bishop=b7,f8; knight=e5; pawn=d4,c5,e6,a7,g7,h7
Counts: white king=1; queen=1; rook=2; bishop=2; knight=1; pawn=6 | black king=1; queen=1; rook=2; bishop=2; knight=1; pawn=6
Values: white total=34; black total=34
Balance: Material is equal.


Prompt:
Starting FEN: r1b1k2r/pp3ppp/n1p4B/8/6n1/P1N2NP1/1PP1B2P/2KR1R2 b kq - 0 19
After the moves h8g8 d1d8 e8d8, what is the resulting position?
State needed for full FEN:
Side to move: black
Castling rights: kq
En passant: none
Halfmove clock: 0
Fullmove number: 19

Answer format: return exactly "Result FEN: <complete six-field FEN>".

Result FEN: r1bk2r1/pp3ppp/n1p4B/8/6n1/P1N2NP1/1PP1B2P/2K2R2 w - - 0 21


Prompt:
Position (FEN): r3qrk1/5pp1/4p2p/pN1p4/4n3/P3P2P/5PP1/1RB1QRK1 w - - 1 21
Show me the board.


Prompt:
Here is the current board:
8 r n b . k b n r
7 p p . . p p p p
6 . . . p . . . .
5 q . P . . . . .
4 . . . . P . . .
3 . . N . . . . .
2 P P P . . P P P
1 R . B Q K B N R
  a b c d e f g h
Write the FEN for this position.
State needed for full FEN:
Side to move: black
Castling rights: KQkq
En passant: none
Halfmove clock: 0
Fullmove number: 1

Answer format: return exactly one complete six-field FEN, with no prefix and no explanation.

rnb1kbnr/pp2pppp/3p4/q1P5/4P3/2N5/PPP2PPP/R1BQKBNR b KQkq - 0 1


Prompt:
FEN: r1bqkb1r/pp2pppp/2n5/4P3/1nB5/5N2/PP3PPP/RNBQ1RK1 b kq -
What piece is on b4?

Answer format: for a square query, return only the piece name or empty; do not include the square. For a locate query, return only space-separated squares.


Prompt:
FEN: 2k5/p6R/1p4r1/2pQ4/8/PP6/8/2K5 b - - 10 44
What is the material count for both sides?

White (5 pieces): 1 king, 2 pawns, 1 queen, 1 rook. Black (5 pieces): 1 king, 3 pawns, 1 rook. White is up 8 point(s) of material.


Prompt:
FEN: 2n5/1k1Q4/1p4r1/pP2rp2/P4R1p/7P/5P1K/5R2 b - - 1 38
What is on c3?

Answer format: return exactly "<square>=<piece>" or "<square>=empty".


Prompt:
FEN: r4b1r/1pp2Qpp/p1kp1p2/1N6/1P1qP3/P2P3P/5PP1/R4RK1 w - - 2 21
What is the compressed FEN row for rank 7?

Answer format: return exactly "rank N: <compressed FEN row>".


Prompt:
FEN: 5rr1/k1p5/pp1p4/3Q3N/6qp/2PNP3/PP4PP/R5K1 w - - 2 30
For square c5, give the FEN row-from-top and file index.

Answer format: return exactly "<square>: file=<file>; rank=<rank>; fen_row_from_top=<1-8>; file_index=<1-8>".

c5: file=c; rank=5; fen_row_from_top=4; file_index=3


Prompt:
FEN: 8/5k2/1p6/3b1p1p/1p2pP1P/1P2Q1PK/P2bN3/2Nr4 w - -
Compressed rank 4 row: 1p2pP1P
Expand it into file cells a through h.

Answer format: return exactly "rank N: a=<cell>; b=<cell>; ...; h=<cell>".


Prompt:
Rank 7 row before: 5b2
File h changes from 1 to k. Rewrite the compressed row.

Answer format: return exactly "rank N: <before-row> -> <after-row>".


Prompt:
Board FEN before: 8/1p3B1k/p2p2p1/q1p1r1Pp/P6P/1P1Q4/2P5/2KR4
Apply square edits: e5 r->1; e7 1->r
Return the resulting board FEN only.

Answer format: return exactly "Result board FEN: <piece-placement-field>".

Result board FEN: 8/1p2rB1k/p2p2p1/q1p3Pp/P6P/1P1Q4/2P5/2KR4


Prompt:
Starting FEN: R6r/2p2pkp/2B3p1/1P4Q1/3P4/6Pb/5P1P/5RK1 b - -
Move: h3f5
List the square lookups and rank edits.

Answer format: return exactly three lines starting "Lookup:", "Squares:", and "Ranks:"; do not include Result FEN.

Lookup: h3=black bishop; f5=empty.
Squares: h3 black bishop->empty; f5 empty->black bishop.
Ranks: rank 3 h b->1; rank 5 f 1->b.


Prompt:
Starting FEN: rnb1kbnr/pp1pqppp/8/2p1p3/2B1P3/2N2N2/PPPP1PPP/R1BQK2R b KQkq - 3 4
Move: b8a6
Use square lookups and rank edits to assemble the resulting full FEN.
State needed for full FEN:
Side to move: black
Castling rights: KQkq
En passant: none
Halfmove clock: 3
Fullmove number: 4

Answer format: include the edit trace and exactly one final line "Result FEN: <complete six-field FEN>".

Move 1: black knight b8a6.
Lookup: b8=black knight; a6=empty.
Squares: b8 black knight->empty; a6 empty->black knight.
Ranks: rank 8 b n->1; rank 6 a 1->n.
Result FEN: r1b1kbnr/pp1pqppp/n7/2p1p3/2B1P3/2N2N2/PPPP1PPP/R1BQK2R w KQkq - 4 5


Prompt:
Starting FEN: r2qk2r/1Rp2ppp/p3p3/8/P1NPnB2/Q3P3/5PPP/5RK1 b kq - 0 19
Move: d8d6
Rewrite the affected compressed FEN rank rows and give Result FEN.
State needed for full FEN:
Side to move: black
Castling rights: kq
En passant: none
Halfmove clock: 0
Fullmove number: 19

Answer format: first line starts "Rows:" and final line is "Result FEN: <complete six-field FEN>".

Rows: rank 8 r2qk2r->r3k2r; rank 6 p3p3->p2qp3.
Result FEN: r3k2r/1Rp2ppp/p2qp3/8/P1NPnB2/Q3P3/5PPP/5RK1 w kq - 1 20


Prompt:
Starting FEN: 2r2rk1/1p2bpp1/3pq2p/2p4P/2Q1P1P1/1P1P1B2/P1P2P2/R3K2R b KQ - 1 21
After the moves c8c6, what is the resulting position?
State needed for full FEN:
Side to move: black
Castling rights: KQ
En passant: none
Halfmove clock: 1
Fullmove number: 21

Answer format: return exactly "Result FEN: <complete six-field FEN>".

Result FEN: 5rk1/1p2bpp1/2rpq2p/2p4P/2Q1P1P1/1P1P1B2/P1P2P2/R3K2R w KQ - 2 22


Prompt:
FEN: r2q1rk1/pppbbppp/1nnp4/4p1P1/4P2P/P1N5/BPPP1P2/R1BQK1NR w KQ - 5 10
List the material inventory by side and piece type.

Answer format: return exactly two lines starting "White inventory:" and "Black inventory:".

White inventory: king=e1; queen=d1; rook=a1,h1; bishop=c1,a2; knight=g1,c3; pawn=b2,c2,d2,f2,a3,e4,h4,g5.
Black inventory: king=g8; queen=d8; rook=a8,f8; bishop=d7,e7; knight=b6,c6; pawn=e5,d6,a7,b7,c7,f7,g7,h7.


Prompt:
FEN: 8/1R6/8/2k5/8/8/8/2K5 b - -
Count each piece type for both sides.

Answer format: return exactly two lines starting "White counts:" and "Black counts:".

White counts: king=1; queen=0; rook=1; bishop=0; knight=0; pawn=0.
Black counts: king=1; queen=0; rook=0; bishop=0; knight=0; pawn=0.


Prompt:
FEN: r2q1rk1/1pp2p1p/p1n2pp1/3b4/3P4/P1R1PN2/1P2BPPP/3Q1RK1 w - - 2 14
Convert the piece counts into material value totals.

Answer format: return exactly two lines starting "White values:" and "Black values:".

White values: king=0; queen=9; rook=10; bishop=3; knight=3; pawn=7; total=32.
Black values: king=0; queen=9; rook=10; bishop=3; knight=3; pawn=7; total=32.


Prompt:
FEN: 8/p3kp1p/1p1p1n2/1P1P4/5p1P/5P2/r5r1/5K2 b - - 1 39
Trace inventory, counts, values, and material balance.

Answer format: return exactly four lines starting "Inventory:", "Counts:", "Values:", and "Balance:".

Inventory: white king=f1; queen=none; rook=none; bishop=none; knight=none; pawn=f3,h4,b5,d5 | black king=e7; queen=none; rook=a2,g2; bishop=none; knight=f6; pawn=f4,b6,d6,a7,f7,h7
Counts: white king=1; queen=0; rook=0; bishop=0; knight=0; pawn=4 | black king=1; queen=0; rook=2; bishop=0; knight=1; pawn=6
Values: white total=4; black total=19
Balance: Black is up 15 point(s) of material.


Prompt:
Starting FEN: r4rk1/pp3ppp/2pb4/3pN1q1/3P4/2N5/PPP2P2/R2Q1R1K b - - 0 1
After the moves a8b8 a2a3 g5d2, what is the resulting position?
State needed for full FEN:
Side to move: black
Castling rights: none
En passant: none
Halfmove clock: 0
Fullmove number: 1

Answer format: return exactly "Result FEN: <complete six-field FEN>".

Result FEN: 1r3rk1/pp3ppp/2pb4/3pN3/3P4/P1N5/1PPq1P2/R2Q1R1K w - - 1 3


Prompt:
Position (FEN): 8/5k2/1p1p4/p1pP1K2/P1B1P3/1P3b2/8/8 b - - 8 39
Show me the board.


1B1qk2r/1b2npbp/pp4p1/n1pp4/P7/2NP4/BPPN2PP/R3QRK1 b k - 0 17

Prompt:
Here is the current board:
8 . B . q k . . r
7 . b . . n p b p
6 p p . . . . p .
5 n . p p . . . .
4 P . . . . . . .
3 . . N P . . . .
2 B P P N . . P P
1 R . . . Q R K .
  a b c d e f g h
Write the FEN for this position.
State needed for full FEN:
Side to move: black
Castling rights: k
En passant: none
Halfmove clock: 0
Fullmove number: 17

Answer format: return exactly one complete six-field FEN, with no prefix and no explanation.


Prompt:
FEN: r2qk2r/p2bbppp/2p2n2/3p4/3p4/5N2/PPPNQPPP/R1B1R1K1 w kq -
What piece is on e7?

Answer format: for a square query, return only the piece name or empty; do not include the square. For a locate query, return only space-separated squares.


Prompt:
FEN: rnb1kb1r/ppp3pp/5p2/3Bp3/4P2q/5Q2/PPPP1PPP/RNB1K1NR b KQkq - 0 5
What is the material count for both sides?

White (16 pieces): 2 bishops, 1 king, 2 knights, 8 pawns, 1 queen, 2 rooks. Black (14 pieces): 2 bishops, 1 king, 1 knight, 7 pawns, 1 queen, 2 rooks. White is up 4 point(s) of material.


Prompt:
FEN: 8/2pk2p1/1pnp4/r3p1B1/2P1PP2/P2K4/1Q5r/6R1 w - - 0 29
What is on h2?

Answer format: return exactly "<square>=<piece>" or "<square>=empty".


Prompt:
FEN: 8/3r4/7Q/8/6k1/8/4K3/8 b - -
What is the compressed FEN row for rank 1?

Answer format: return exactly "rank N: <compressed FEN row>".


Prompt:
FEN: 8/r5pk/1R3p1p/8/1pN5/7P/r5PK/8 b - - 5 44
For square h2, give the FEN row-from-top and file index.

Answer format: return exactly "<square>: file=<file>; rank=<rank>; fen_row_from_top=<1-8>; file_index=<1-8>".

h2: file=h; rank=2; fen_row_from_top=7; file_index=8


Prompt:
FEN: rn1q1rk1/pp3ppp/5n2/1Pb1B3/8/3BP2P/2P1QPP1/RN2K2R b KQ - 0 12
Compressed rank 7 row: pp3ppp
Expand it into file cells a through h.

Answer format: return exactly "rank N: a=<cell>; b=<cell>; ...; h=<cell>".


rnbqkb1r/ppp2ppp/1n6/3Pp3/4P3/2N5/PP3PPP/R1BQKBNR b KQkq -

Prompt:
Rank 7 row before: ppp2ppp
File d changes from 1 to k. Rewrite the compressed row.

Answer format: return exactly "rank N: <before-row> -> <after-row>".


Prompt:
Board FEN before: k3rb2/1p3qp1/pBp1nr2/5B2/4P1QP/1P3P2/P7/1K1R3R
Apply square edits: e8 r->1; b8 1->r
Return the resulting board FEN only.

Answer format: return exactly "Result board FEN: <piece-placement-field>".

Result board FEN: kr3b2/1p3qp1/pBp1nr2/5B2/4P1QP/1P3P2/P7/1K1R3R


Prompt:
Starting FEN: 8/7p/4k3/4p1p1/2Np3P/1rbR1P2/8/7K w - - 0 39
Move: d3e3
List the square lookups and rank edits.

Answer format: return exactly three lines starting "Lookup:", "Squares:", and "Ranks:"; do not include Result FEN.

Lookup: d3=white rook; e3=empty.
Squares: d3 white rook->empty; e3 empty->white rook.
Ranks: rank 3 d R->1; rank 3 e 1->R.


Prompt:
Starting FEN: r3k3/1p1n1p1p/p3p1p1/8/P1PB1PP1/1P5P/4K3/3R4 b - - 0 1
Move: a8d8
Use square lookups and rank edits to assemble the resulting full FEN.
State needed for full FEN:
Side to move: black
Castling rights: none
En passant: none
Halfmove clock: 0
Fullmove number: 1

Answer format: include the edit trace and exactly one final line "Result FEN: <complete six-field FEN>".

Move 1: black rook a8d8.
Lookup: a8=black rook; d8=empty.
Squares: a8 black rook->empty; d8 empty->black rook.
Ranks: rank 8 a r->1; rank 8 d 1->r.
Result FEN: 3rk3/1p1n1p1p/p3p1p1/8/P1PB1PP1/1P5P/4K3/3R4 w - - 1 2


Prompt:
Starting FEN: 4r3/4Pk2/1R2R1pp/2P2p2/8/2r5/6PP/6K1 b - - 3 43
Move: e8g8
Rewrite the affected compressed FEN rank rows and give Result FEN.
State needed for full FEN:
Side to move: black
Castling rights: none
En passant: none
Halfmove clock: 3
Fullmove number: 43

Answer format: first line starts "Rows:" and final line is "Result FEN: <complete six-field FEN>".


Prompt:
Starting FEN: 2kr1b1r/1pp1pppp/p1n2n2/q4b2/8/P1NP1N2/1PPBBPPP/R2Q1RK1 b - - 0 9
After the moves f5h3, what is the resulting position?
State needed for full FEN:
Side to move: black
Castling rights: none
En passant: none
Halfmove clock: 0
Fullmove number: 9

Answer format: return exactly "Result FEN: <complete six-field FEN>".

Result FEN: 2kr1b1r/1pp1pppp/p1n2n2/q7/8/P1NP1N1b/1PPBBPPP/R2Q1RK1 w - - 1 10


Prompt:
FEN: r3k1nr/p4pbp/1qbp2p1/8/Rp2P3/3B1P2/1P2NRPP/1N1Q2K1 w kq - 4 18
List the material inventory by side and piece type.

Answer format: return exactly two lines starting "White inventory:" and "Black inventory:".

White inventory: king=g1; queen=d1; rook=f2,a4; bishop=d3; knight=b1,e2; pawn=b2,g2,h2,f3,e4.
Black inventory: king=e8; queen=b6; rook=a8,h8; bishop=c6,g7; knight=g8; pawn=b4,d6,g6,a7,f7,h7.


Prompt:
FEN: r4r1k/pp5p/1n1p4/3P3q/2PP1p2/P4P2/2QBK3/R5R1 b - - 0 26
Count each piece type for both sides.

Answer format: return exactly two lines starting "White counts:" and "Black counts:".

White counts: king=1; queen=1; rook=2; bishop=1; knight=0; pawn=5.
Black counts: king=1; queen=1; rook=2; bishop=0; knight=1; pawn=5.


Prompt:
FEN: rn1qkb1r/ppp1ppp1/5nbp/8/7P/5NN1/PPPP1PP1/R1BQKB1R w KQkq -
Convert the piece counts into material value totals.

Answer format: return exactly two lines starting "White values:" and "Black values:".

White values: king=0; queen=9; rook=10; bishop=6; knight=6; pawn=7; total=38.
Black values: king=0; queen=9; rook=10; bishop=6; knight=6; pawn=7; total=38.


Prompt:
FEN: r2qk2r/pp3ppp/2n2n2/4p3/1bP3b1/3P1N2/PP1BBPPP/RN1QK2R b KQkq - 2 8
Trace inventory, counts, values, and material balance.

Answer format: return exactly four lines starting "Inventory:", "Counts:", "Values:", and "Balance:".

Inventory: white king=e1; queen=d1; rook=a1,h1; bishop=d2,e2; knight=b1,f3; pawn=a2,b2,f2,g2,h2,d3,c4 | black king=e8; queen=d8; rook=a8,h8; bishop=b4,g4; knight=c6,f6; pawn=e5,a7,b7,f7,g7,h7
Counts: white king=1; queen=1; rook=2; bishop=2; knight=2; pawn=7 | black king=1; queen=1; rook=2; bishop=2; knight=2; pawn=6
Values: white total=38; black total=37
Balance: White is up 1 point(s) of material.


Prompt:
Starting FEN: 8/1b6/1Pp1P3/3p3k/5K2/3BP2P/8/8 b - - 0 51
After the moves b7c8 f4f3 c6c5, what is the resulting position?
State needed for full FEN:
Side to move: black
Castling rights: none
En passant: none
Halfmove clock: 0
Fullmove number: 51

Answer format: return exactly "Result FEN: <complete six-field FEN>".


Prompt:
Position (FEN): r3kbnr/pb2q1pp/1pp5/3pn3/3P1P2/2NB4/PP4PP/R1BQ1RK1 w kq - 0 12
Show me the board.


r2qk2r/1ppb1ppp/p1n2n2/b3p1B1/N1BpP3/P2P1N2/1PP2PPP/R2Q1RK1 w kq - 0 11

Prompt:
Here is the current board:
8 r . . q k . . r
7 . p p b . p p p
6 p . n . . n . .
5 b . . . p . B .
4 N . B p P . . .
3 P . . P . N . .
2 . P P . . P P P
1 R . . Q . R K .
  a b c d e f g h
Write the FEN for this position.
State needed for full FEN:
Side to move: white
Castling rights: kq
En passant: none
Halfmove clock: 0
Fullmove number: 11

Answer format: return exactly one complete six-field FEN, with no prefix and no explanation.


Prompt:
FEN: r3k1n1/5p2/2pp2p1/pp2p3/4P3/PQPPBq1B/1P3P1p/R3K2R w Qq - 0 23
What piece is on g6?

Answer format: for a square query, return only the piece name or empty; do not include the square. For a locate query, return only space-separated squares.


Prompt:
FEN: r1bqkb1r/p4p1p/4p1p1/3pP3/1ppP4/2P4Q/PPBN1PPP/R3K2R w KQkq -
What is the material count for both sides?

White (14 pieces): 1 bishop, 1 king, 1 knight, 8 pawns, 1 queen, 2 rooks. Black (14 pieces): 2 bishops, 1 king, 8 pawns, 1 queen, 2 rooks. Material is equal.


Prompt:
FEN: k7/8/1K6/B3N3/8/8/8/8 w - -
What is on d6?

Answer format: return exactly "<square>=<piece>" or "<square>=empty".


Prompt:
FEN: r4rk1/1pp1b3/p3pp1p/8/P3q3/5NP1/1P2PPKP/R1QR4 w - -
What is the compressed FEN row for rank 4?

Answer format: return exactly "rank N: <compressed FEN row>".


Prompt:
FEN: 8/3k1pp1/4p2p/3pP3/1Pp5/1PKn1N1P/5PP1/8 b - -
For square d4, give the FEN row-from-top and file index.

Answer format: return exactly "<square>: file=<file>; rank=<rank>; fen_row_from_top=<1-8>; file_index=<1-8>".

d4: file=d; rank=4; fen_row_from_top=5; file_index=4


Prompt:
FEN: rnbqk2r/ppppppbp/6p1/8/2PPn2P/5N2/PP3PP1/RNBQKB1R b KQkq -
Compressed rank 7 row: ppppppbp
Expand it into file cells a through h.

Answer format: return exactly "rank N: a=<cell>; b=<cell>; ...; h=<cell>".

rank 7: a=p; b=p; c=p; d=p; e=p; f=p; g=b; h=p


Prompt:
Rank 8 row before: 2r2rk1
File h changes from 1 to k. Rewrite the compressed row.

Answer format: return exactly "rank N: <before-row> -> <after-row>".


rn1r2k1/pq2bp1p/bp2p1p1/3pPP2/B2P4/4B3/PP2N1PP/2RQ1RK1 b - -

Prompt:
Board FEN before: rn1r2k1/pq2bp1p/bp2p1p1/3pPP2/B2P4/4B3/PP2N1PP/2RQ1RK1
Apply square edits: e7 b->1; h4 1->b
Return the resulting board FEN only.

Answer format: return exactly "Result board FEN: <piece-placement-field>".

Result board FEN: rn1r2k1/pq3p1p/bp2p1p1/3pPP2/B2P3b/4B3/PP2N1PP/2RQ1RK1


Prompt:
Starting FEN: r1bqkb1r/pp1p1ppp/4pn2/2p1n3/2P1P3/2NP2P1/PP2NP1P/R1BQKB1R b KQkq -
Move: e5f3
List the square lookups and rank edits.

Answer format: return exactly three lines starting "Lookup:", "Squares:", and "Ranks:"; do not include Result FEN.

Lookup: e5=black knight; f3=empty.
Squares: e5 black knight->empty; f3 empty->black knight.
Ranks: rank 5 e n->1; rank 3 f 1->n.


Prompt:
Starting FEN: 3r2k1/1b3pbp/pq3np1/1p6/1PpN4/P1B1PP2/2Q3PP/3RN1K1 w - - 0 1
Move: d1d3
Use square lookups and rank edits to assemble the resulting full FEN.
State needed for full FEN:
Side to move: white
Castling rights: none
En passant: none
Halfmove clock: 0
Fullmove number: 1

Answer format: include the edit trace and exactly one final line "Result FEN: <complete six-field FEN>".

Move 1: white rook d1d3.
Lookup: d1=white rook; d3=empty.
Squares: d1 white rook->empty; d3 empty->white rook.
Ranks: rank 1 d R->1; rank 3 d 1->R.
Result FEN: 3r2k1/1b3pbp/pq3np1/1p6/1PpN4/P1BRPP2/2Q3PP/4N1K1 b - - 1 1


Prompt:
Starting FEN: 2rr4/2p2kpp/p3Rp2/1pNn4/1P1P4/P3P3/5PPP/5RK1 b - - 0 24
Move: d8d6
Rewrite the affected compressed FEN rank rows and give Result FEN.
State needed for full FEN:
Side to move: black
Castling rights: none
En passant: none
Halfmove clock: 0
Fullmove number: 24

Answer format: first line starts "Rows:" and final line is "Result FEN: <complete six-field FEN>".

Rows: rank 8 2rr4->2r5; rank 6 p3Rp2->p2rRp2.
Result FEN: 2r5/2p2kpp/p2rRp2/1pNn4/1P1P4/P3P3/5PPP/5RK1 w - - 1 25


Prompt:
Starting FEN: 2b2rk1/1p2qpp1/3b1n1p/8/8/3BPN2/2Q2PPP/B4RK1 b - - 1 21
After the moves b7b6, what is the resulting position?
State needed for full FEN:
Side to move: black
Castling rights: none
En passant: none
Halfmove clock: 1
Fullmove number: 21

Answer format: return exactly "Result FEN: <complete six-field FEN>".

Result FEN: 2b2rk1/4qpp1/1p1b1n1p/8/8/3BPN2/2Q2PPP/B4RK1 w - - 0 22


Prompt:
FEN: 8/8/8/8/3pk3/8/8/3K4 w - -
List the material inventory by side and piece type.

Answer format: return exactly two lines starting "White inventory:" and "Black inventory:".

White inventory: king=d1; queen=none; rook=none; bishop=none; knight=none; pawn=none.
Black inventory: king=e4; queen=none; rook=none; bishop=none; knight=none; pawn=d4.


Prompt:
FEN: 8/8/R5p1/P1pk3b/3p1P1P/3K4/7r/8 w - - 1 47
Count each piece type for both sides.

Answer format: return exactly two lines starting "White counts:" and "Black counts:".

White counts: king=1; queen=0; rook=1; bishop=0; knight=0; pawn=3.
Black counts: king=1; queen=0; rook=1; bishop=1; knight=0; pawn=3.


Prompt:
FEN: 8/2K5/3N4/2k5/8/8/7B/8 w - -
Convert the piece counts into material value totals.

Answer format: return exactly two lines starting "White values:" and "Black values:".

White values: king=0; queen=0; rook=0; bishop=3; knight=3; pawn=0; total=6.
Black values: king=0; queen=0; rook=0; bishop=0; knight=0; pawn=0; total=0.


Prompt:
FEN: rnbqk1nr/pp3pb1/3p2pp/2pPp3/2P1P3/3B4/PP2NPPP/RNBQ1RK1 b kq - 3 7
Trace inventory, counts, values, and material balance.

Answer format: return exactly four lines starting "Inventory:", "Counts:", "Values:", and "Balance:".

Inventory: white king=g1; queen=d1; rook=a1,f1; bishop=c1,d3; knight=b1,e2; pawn=a2,b2,f2,g2,h2,c4,e4,d5 | black king=e8; queen=d8; rook=a8,h8; bishop=g7,c8; knight=b8,g8; pawn=c5,e5,d6,g6,h6,a7,b7,f7
Counts: white king=1; queen=1; rook=2; bishop=2; knight=2; pawn=8 | black king=1; queen=1; rook=2; bishop=2; knight=2; pawn=8
Values: white total=39; black total=39
Balance: Material is equal.


Prompt:
Starting FEN: 7r/1kp5/1p1pRp1r/P2R1P2/1pP3p1/6K1/2P4P/8 b - - 2 31
After the moves h8e8 d5d1 h6g6, what is the resulting position?
State needed for full FEN:
Side to move: black
Castling rights: none
En passant: none
Halfmove clock: 2
Fullmove number: 31

Answer format: return exactly "Result FEN: <complete six-field FEN>".


Prompt:
Position (FEN): 3r4/R2bq2k/4p1Rp/1p1pP3/1Pp2P2/2P4P/5Q2/4KB2 w - - 5 36
Show me the board.


Prompt:
Here is the current board:
8 . . . . . . . r
7 . . . k . . . P
6 . . p . . . . .
5 . . . p . p . R
4 . . . P . P . .
3 . . . . P . . .
2 . . . K . . . .
1 . . . . . . . .
  a b c d e f g h
Write the FEN for this position.
State needed for full FEN:
Side to move: white
Castling rights: none
En passant: none
Halfmove clock: 9
Fullmove number: 71

Answer format: return exactly one complete six-field FEN, with no prefix and no explanation.


Prompt:
FEN: rnbqkb1r/1pp2ppp/5n2/p2p4/8/PB6/1PPP1PPP/RNBQK1NR w KQkq -
What piece is on d5?

Answer format: for a square query, return only the piece name or empty; do not include the square. For a locate query, return only space-separated squares.


Prompt:
FEN: b2r3r/k3qp1p/pn3np1/Nppp4/4PQ2/P1N2PPB/1PP4P/1K1RR3 b - -
What is the material count for both sides?

White (14 pieces): 1 bishop, 1 king, 2 knights, 7 pawns, 1 queen, 2 rooks. Black (14 pieces): 1 bishop, 1 king, 2 knights, 7 pawns, 1 queen, 2 rooks. Material is equal.


Prompt:
FEN: r2qkb1r/ppp1pp1p/2np1np1/8/2PP2b1/1P2PN2/PB3PPP/RN1QKB1R w KQkq -
What is on g1?

Answer format: return exactly "<square>=<piece>" or "<square>=empty".


Prompt:
FEN: rnbqkb1r/p3pppp/2pp4/8/Np2n3/1B3N2/PPPPQPPP/R1B1K2R b KQkq -
What is the compressed FEN row for rank 7?

Answer format: return exactly "rank N: <compressed FEN row>".


Prompt:
FEN: 1r3rk1/p1p5/3p3p/2bPppp1/5P2/3P2Bq/PPPQ1P1P/R4RK1 w - -
For square d1, give the FEN row-from-top and file index.

Answer format: return exactly "<square>: file=<file>; rank=<rank>; fen_row_from_top=<1-8>; file_index=<1-8>".

d1: file=d; rank=1; fen_row_from_top=8; file_index=4


Prompt:
FEN: 6r1/pp3p1p/2kp4/2p5/8/2q3P1/3R1P1P/4R1K1 w - - 2 30
Compressed rank 7 row: pp3p1p
Expand it into file cells a through h.

Answer format: return exactly "rank N: a=<cell>; b=<cell>; ...; h=<cell>".


Prompt:
Rank 5 row before: RP3kp1
File d changes from 1 to b. Rewrite the compressed row.

Answer format: return exactly "rank N: <before-row> -> <after-row>".


Prompt:
Board FEN before: r1b1r1k1/pp3p1p/3b2p1/2p4q/2B5/2B3P1/PP3P1P/R3R1K1
Apply square edits: c4 B->1; e6 1->B
Return the resulting board FEN only.

Answer format: return exactly "Result board FEN: <piece-placement-field>".

Result board FEN: r1b1r1k1/pp3p1p/3bB1p1/2p4q/8/2B3P1/PP3P1P/R3R1K1


Prompt:
Starting FEN: 8/7p/4k3/5p2/p2bpK1P/8/8/2B5 b - - 1 43
Move: d4e5
List the square lookups and rank edits.

Answer format: return exactly three lines starting "Lookup:", "Squares:", and "Ranks:"; do not include Result FEN.

Lookup: d4=black bishop; e5=empty.
Squares: d4 black bishop->empty; e5 empty->black bishop.
Ranks: rank 4 d b->1; rank 5 e 1->b.


Prompt:
Starting FEN: 3r4/2p3pk/p2n3p/1p6/4R3/2P2P1P/P5K1/4R3 w - - 0 31
Move: e4h4
Use square lookups and rank edits to assemble the resulting full FEN.
State needed for full FEN:
Side to move: white
Castling rights: none
En passant: none
Halfmove clock: 0
Fullmove number: 31

Answer format: include the edit trace and exactly one final line "Result FEN: <complete six-field FEN>".

Move 1: white rook e4h4.
Lookup: e4=white rook; h4=empty.
Squares: e4 white rook->empty; h4 empty->white rook.
Ranks: rank 4 e R->1; rank 4 h 1->R.
Result FEN: 3r4/2p3pk/p2n3p/1p6/7R/2P2P1P/P5K1/4R3 b - - 1 31


Prompt:
Starting FEN: r1b1k2r/2p2p1p/p3pp2/np6/P1pP4/1qN1P3/4BPPP/2RQ1RK1 w kq - 0 1
Move: f1e1
Rewrite the affected compressed FEN rank rows and give Result FEN.
State needed for full FEN:
Side to move: white
Castling rights: kq
En passant: none
Halfmove clock: 0
Fullmove number: 1

Answer format: first line starts "Rows:" and final line is "Result FEN: <complete six-field FEN>".

Rows: rank 1 2RQ1RK1->2RQR1K1.
Result FEN: r1b1k2r/2p2p1p/p3pp2/np6/P1pP4/1qN1P3/4BPPP/2RQR1K1 b kq - 1 1


Prompt:
Starting FEN: r3r1k1/pq2bp2/R5p1/1p3p2/Q1pP1P2/2P4P/PP1N2P1/5RK1 w - - 0 1
After the moves a6b6, what is the resulting position?
State needed for full FEN:
Side to move: white
Castling rights: none
En passant: none
Halfmove clock: 0
Fullmove number: 1

Answer format: return exactly "Result FEN: <complete six-field FEN>".

Result FEN: r3r1k1/pq2bp2/1R4p1/1p3p2/Q1pP1P2/2P4P/PP1N2P1/5RK1 b - - 1 1


Prompt:
FEN: r2q1rk1/4ppbp/3p1np1/2pP1b2/1n6/1PN3P1/PB1QPPBP/R4KNR b - -
List the material inventory by side and piece type.

Answer format: return exactly two lines starting "White inventory:" and "Black inventory:".

White inventory: king=f1; queen=d2; rook=a1,h1; bishop=b2,g2; knight=g1,c3; pawn=a2,e2,f2,h2,b3,g3,d5.
Black inventory: king=g8; queen=d8; rook=a8,f8; bishop=f5,g7; knight=b4,f6; pawn=c5,d6,g6,e7,f7,h7.


Prompt:
FEN: 6k1/5p2/4n1p1/P6p/6Q1/7P/3pB1PK/4q3 w - -
Count each piece type for both sides.

Answer format: return exactly two lines starting "White counts:" and "Black counts:".

White counts: king=1; queen=1; rook=0; bishop=1; knight=0; pawn=3.
Black counts: king=1; queen=1; rook=0; bishop=0; knight=1; pawn=4.


Prompt:
FEN: r5k1/ppp2ppp/6q1/8/2P1bP2/2RP4/3KRN1P/8 w - - 4 31
Convert the piece counts into material value totals.

Answer format: return exactly two lines starting "White values:" and "Black values:".

White values: king=0; queen=0; rook=10; bishop=0; knight=3; pawn=4; total=17.
Black values: king=0; queen=9; rook=5; bishop=3; knight=0; pawn=6; total=23.


Prompt:
FEN: r7/pp2kPp1/2p2bB1/1q3P1Q/N1b5/4p3/PP4PP/4R2K b - -
Trace inventory, counts, values, and material balance.

Answer format: return exactly four lines starting "Inventory:", "Counts:", "Values:", and "Balance:".

Inventory: white king=h1; queen=h5; rook=e1; bishop=g6; knight=a4; pawn=a2,b2,g2,h2,f5,f7 | black king=e7; queen=b5; rook=a8; bishop=c4,f6; knight=none; pawn=e3,c6,a7,b7,g7
Counts: white king=1; queen=1; rook=1; bishop=1; knight=1; pawn=6 | black king=1; queen=1; rook=1; bishop=2; knight=0; pawn=5
Values: white total=26; black total=25
Balance: White is up 1 point(s) of material.


Prompt:
Starting FEN: r2q1bk1/1p2rpp1/p2p1nbp/2pP4/4P3/P1NB3P/1P1N1PP1/R2QR1K1 b - - 1 18
After the moves d8a5 d3c4 f6g4, what is the resulting position?
State needed for full FEN:
Side to move: black
Castling rights: none
En passant: none
Halfmove clock: 1
Fullmove number: 18

Answer format: return exactly "Result FEN: <complete six-field FEN>".

Result FEN: r4bk1/1p2rpp1/p2p2bp/q1pP4/2B1P1n1/P1N4P/1P1N1PP1/R2QR1K1 w - - 4 20


Prompt:
Position (FEN): 8/8/8/5k2/1N1B4/3K4/8/8 w - -
Show me the board.


Prompt:
Here is the current board:
8 r . b q . r k .
7 . . p . . p p p
6 p . n p . n . .
5 . p . . p . . .
4 . . . . P . . .
3 P B . P . N . P
2 . P P N . P P .
1 R . . Q . R K .
  a b c d e f g h
Write the FEN for this position.
State needed for full FEN:
Side to move: black
Castling rights: none
En passant: none
Halfmove clock: 1
Fullmove number: 12

Answer format: return exactly one complete six-field FEN, with no prefix and no explanation.


Prompt:
FEN: r1bqk2r/ppp2ppp/2n5/3Np1N1/1bB5/8/PPPP1PPP/R1BQK2R b KQkq - 0 7
What piece is on c6?

Answer format: for a square query, return only the piece name or empty; do not include the square. For a locate query, return only space-separated squares.


Prompt:
FEN: r1bq1rk1/1pp1npp1/p2p3p/3Pp3/4P3/3P1N1P/PP2BPP1/R2Q1RK1 w - - 1 13
What is the material count for both sides?

White (14 pieces): 1 bishop, 1 king, 1 knight, 8 pawns, 1 queen, 2 rooks. Black (14 pieces): 1 bishop, 1 king, 1 knight, 8 pawns, 1 queen, 2 rooks. Material is equal.


Prompt:
FEN: 8/pp2k1p1/3nN2p/1P2pp2/7P/1B3PP1/7K/4q3 b - -
What is on h4?

Answer format: return exactly "<square>=<piece>" or "<square>=empty".


Prompt:
FEN: r1bqkb1r/pppp1pp1/5nn1/3Pp1Bp/2P1P2P/2N5/PP3PP1/R2QKBNR b KQkq -
What is the compressed FEN row for rank 8?

Answer format: return exactly "rank N: <compressed FEN row>".


Prompt:
FEN: 8/8/8/5BK1/7P/8/5kP1/8 w - -
For square b5, give the FEN row-from-top and file index.

Answer format: return exactly "<square>: file=<file>; rank=<rank>; fen_row_from_top=<1-8>; file_index=<1-8>".

b5: file=b; rank=5; fen_row_from_top=4; file_index=2


Prompt:
FEN: 8/8/8/8/Q3K3/3p4/3k4/8 b - - 3 74
Compressed rank 3 row: 3p4
Expand it into file cells a through h.

Answer format: return exactly "rank N: a=<cell>; b=<cell>; ...; h=<cell>".


rnbqkb1r/pppppp1p/8/6p1/3P1B2/8/PPPNPKPP/R2Q1BNR b kq - 0 5

Prompt:
Rank 8 row before: rnbqkb1r
File b changes from n to 1. Rewrite the compressed row.

Answer format: return exactly "rank N: <before-row> -> <after-row>".


Prompt:
Board FEN before: 8/p6p/3R1pp1/k7/2r2B2/2P5/PP3PPP/5RK1
Apply square edits: a2 P->1; a3 1->P
Return the resulting board FEN only.

Answer format: return exactly "Result board FEN: <piece-placement-field>".

Result board FEN: 8/p6p/3R1pp1/k7/2r2B2/P1P5/1P3PPP/5RK1


Prompt:
Starting FEN: 3r1k2/p2n1r2/1p1Q4/8/3p4/2P4P/PP3PP1/4R1K1 b - - 3 33
Move: f8g8
List the square lookups and rank edits.

Answer format: return exactly three lines starting "Lookup:", "Squares:", and "Ranks:"; do not include Result FEN.

Lookup: f8=black king; g8=empty.
Squares: f8 black king->empty; g8 empty->black king.
Ranks: rank 8 f k->1; rank 8 g 1->k.


Prompt:
Starting FEN: 8/PK2q3/8/4B3/8/8/8/5k2 w - - 0 1
Move: b7a8
Use square lookups and rank edits to assemble the resulting full FEN.
State needed for full FEN:
Side to move: white
Castling rights: none
En passant: none
Halfmove clock: 0
Fullmove number: 1

Answer format: include the edit trace and exactly one final line "Result FEN: <complete six-field FEN>".

Move 1: white king b7a8.
Lookup: b7=white king; a8=empty.
Squares: b7 white king->empty; a8 empty->white king.
Ranks: rank 7 b K->1; rank 8 a 1->K.
Result FEN: K7/P3q3/8/4B3/8/8/8/5k2 b - - 1 1


Prompt:
Starting FEN: 5r1k/ppnq2bp/3p2b1/3Pp1B1/1P2N3/P1N2Q2/6PP/5RK1 w - - 0 1
Move: e4g3
Rewrite the affected compressed FEN rank rows and give Result FEN.
State needed for full FEN:
Side to move: white
Castling rights: none
En passant: none
Halfmove clock: 0
Fullmove number: 1

Answer format: first line starts "Rows:" and final line is "Result FEN: <complete six-field FEN>".

Rows: rank 4 1P2N3->1P6; rank 3 P1N2Q2->P1N2QN1.
Result FEN: 5r1k/ppnq2bp/3p2b1/3Pp1B1/1P6/P1N2QN1/6PP/5RK1 b - - 1 1


Prompt:
Starting FEN: r1bq2k1/1p3pp1/2p3np/p3p3/PbB1P1P1/2N3B1/1PP1QPP1/4R1K1 w - - 0 20
After the moves c3d5, what is the resulting position?
State needed for full FEN:
Side to move: white
Castling rights: none
En passant: none
Halfmove clock: 0
Fullmove number: 20

Answer format: return exactly "Result FEN: <complete six-field FEN>".

Result FEN: r1bq2k1/1p3pp1/2p3np/p2Np3/PbB1P1P1/6B1/1PP1QPP1/4R1K1 b - - 1 20


Prompt:
FEN: r3kb1r/ppp2ppp/2n5/4P3/8/3P4/PP3PPP/RNB1K2R w KQkq -
List the material inventory by side and piece type.

Answer format: return exactly two lines starting "White inventory:" and "Black inventory:".

White inventory: king=e1; queen=none; rook=a1,h1; bishop=c1; knight=b1; pawn=a2,b2,f2,g2,h2,d3,e5.
Black inventory: king=e8; queen=none; rook=a8,h8; bishop=f8; knight=c6; pawn=a7,b7,c7,f7,g7,h7.


Prompt:
FEN: 1r4k1/p1p3pp/4pn2/3r4/4p3/B6P/PPP2PP1/R2R2K1 w - -
Count each piece type for both sides.

Answer format: return exactly two lines starting "White counts:" and "Black counts:".

White counts: king=1; queen=0; rook=2; bishop=1; knight=0; pawn=6.
Black counts: king=1; queen=0; rook=2; bishop=0; knight=1; pawn=6.


Prompt:
FEN: r1b2rk1/2pqbppp/p1n1p3/1p3n2/B7/2NP1N2/PPPB1PPP/R2Q1RK1 w - - 0 12
Convert the piece counts into material value totals.

Answer format: return exactly two lines starting "White values:" and "Black values:".

White values: king=0; queen=9; rook=10; bishop=6; knight=6; pawn=7; total=38.
Black values: king=0; queen=9; rook=10; bishop=6; knight=6; pawn=7; total=38.


Prompt:
FEN: r3kb1r/2qbpp2/n1pp1np1/pp5p/3PP3/PBN1BPN1/1PP3PP/R2Q1RK1 w kq -
Trace inventory, counts, values, and material balance.

Answer format: return exactly four lines starting "Inventory:", "Counts:", "Values:", and "Balance:".

Inventory: white king=g1; queen=d1; rook=a1,f1; bishop=b3,e3; knight=c3,g3; pawn=b2,c2,g2,h2,a3,f3,d4,e4 | black king=e8; queen=c7; rook=a8,h8; bishop=d7,f8; knight=a6,f6; pawn=a5,b5,h5,c6,d6,g6,e7,f7
Counts: white king=1; queen=1; rook=2; bishop=2; knight=2; pawn=8 | black king=1; queen=1; rook=2; bishop=2; knight=2; pawn=8
Values: white total=39; black total=39
Balance: Material is equal.


Prompt:
Starting FEN: 8/B2k1bp1/5p1p/1p1BnP1P/1P1K2P1/8/8/8 b - - 0 1
After the moves d7c7 d5c4, what is the resulting position?
State needed for full FEN:
Side to move: black
Castling rights: none
En passant: none
Halfmove clock: 0
Fullmove number: 1

Answer format: return exactly "Result FEN: <complete six-field FEN>".


Prompt:
Position (FEN): rn1qkbnr/5bpp/2pp4/1p6/1p2P1P1/2N2N1P/P1P2P2/R1BQKB1R w KQkq - 0 11
Show me the board.


Prompt:
Here is the current board:
8 . . . . . . . .
7 . . . . . . . .
6 . . . . . . . .
5 . . k . . . . .
4 . . . . . . . .
3 . B B . K . . .
2 . . . . . . . .
1 . . . . . . . .
  a b c d e f g h
Write the FEN for this position.
State needed for full FEN:
Side to move: black
Castling rights: none
En passant: none
Halfmove clock: 0
Fullmove number: 1

Answer format: return exactly one complete six-field FEN, with no prefix and no explanation.


Prompt:
FEN: 4Q3/8/1k6/2NK4/8/8/8/8 w - -
What piece is on e8?

Answer format: for a square query, return only the piece name or empty; do not include the square. For a locate query, return only space-separated squares.


Prompt:
FEN: 8/3k2p1/p5b1/5pBp/P2p3P/1r3PK1/6P1/4R3 w - - 0 42
What is the material count for both sides?

White (7 pieces): 1 bishop, 1 king, 4 pawns, 1 rook. Black (8 pieces): 1 bishop, 1 king, 5 pawns, 1 rook. Black is up 1 point(s) of material.


Prompt:
FEN: r1bqk2r/1p1p1ppp/p1n2b2/4p2Q/2B1P3/N7/PPP2PPP/R1B2RK1 b kq - 1 12
What is on f8?

Answer format: return exactly "<square>=<piece>" or "<square>=empty".


Prompt:
FEN: 8/8/3k4/8/2Q5/4K3/8/8 b - -
What is the compressed FEN row for rank 8?

Answer format: return exactly "rank N: <compressed FEN row>".


Prompt:
FEN: 2k5/1pp4p/p6n/4R1N1/1P4pP/2PK4/6r1/8 w - - 0 29
For square h7, give the FEN row-from-top and file index.

Answer format: return exactly "<square>: file=<file>; rank=<rank>; fen_row_from_top=<1-8>; file_index=<1-8>".

h7: file=h; rank=7; fen_row_from_top=2; file_index=8


Prompt:
FEN: 1n1r2k1/rpb2ppp/1N2b3/p1p5/P2p4/1P3B2/2P2PPP/R1BR2K1 w - -
Compressed rank 4 row: P2p4
Expand it into file cells a through h.

Answer format: return exactly "rank N: a=<cell>; b=<cell>; ...; h=<cell>".


Prompt:
Rank 1 row before: 2KR3R
File e changes from 1 to R. Rewrite the compressed row.

Answer format: return exactly "rank N: <before-row> -> <after-row>".


rnbqkb1r/ppp2ppp/4pn2/8/N1PpP3/8/PP1P1PPP/R1BQKBNR w KQkq -

Prompt:
Board FEN before: rnbqkb1r/ppp2ppp/4pn2/8/N1PpP3/8/PP1P1PPP/R1BQKBNR
Apply square edits: b2 P->1; b4 1->P
Return the resulting board FEN only.

Answer format: return exactly "Result board FEN: <piece-placement-field>".

Result board FEN: rnbqkb1r/ppp2ppp/4pn2/8/NPPpP3/8/P2P1PPP/R1BQKBNR


Prompt:
Starting FEN: r3kb1r/p2bq2p/1p1p2p1/B7/3PB3/5N2/PPQ3PP/2KR3R b kq - 2 20
Move: e8d8
List the square lookups and rank edits.

Answer format: return exactly three lines starting "Lookup:", "Squares:", and "Ranks:"; do not include Result FEN.

Lookup: e8=black king; d8=empty.
Squares: e8 black king->empty; d8 empty->black king.
Ranks: rank 8 e k->1; rank 8 d 1->k.


Prompt:
Starting FEN: r4rk1/pp3ppp/4p3/8/2p1n3/P3PN2/2P2PPP/R4RK1 w - - 0 16
Move: h2h4
Use square lookups and rank edits to assemble the resulting full FEN.
State needed for full FEN:
Side to move: white
Castling rights: none
En passant: none
Halfmove clock: 0
Fullmove number: 16

Answer format: include the edit trace and exactly one final line "Result FEN: <complete six-field FEN>".

Move 1: white pawn h2h4.
Lookup: h2=white pawn; h4=empty.
Squares: h2 white pawn->empty; h4 empty->white pawn.
Ranks: rank 2 h P->1; rank 4 h 1->P.
Result FEN: r4rk1/pp3ppp/4p3/8/2p1n2P/P3PN2/2P2PP1/R4RK1 b - - 0 16


Prompt:
Starting FEN: r2qk2r/pp1n1ppp/2pbpn2/3p3b/2PP4/3BPN1P/PP1N1PP1/R1BQ1RK1 w kq - 0 1
Move: d1e1
Rewrite the affected compressed FEN rank rows and give Result FEN.
State needed for full FEN:
Side to move: white
Castling rights: kq
En passant: none
Halfmove clock: 0
Fullmove number: 1

Answer format: first line starts "Rows:" and final line is "Result FEN: <complete six-field FEN>".

Rows: rank 1 R1BQ1RK1->R1B1QRK1.
Result FEN: r2qk2r/pp1n1ppp/2pbpn2/3p3b/2PP4/3BPN1P/PP1N1PP1/R1B1QRK1 b kq - 1 1


Prompt:
Starting FEN: 1k4r1/pn2N2R/1p1p1p2/2pP3B/2P1Pp2/q1P5/5RP1/6K1 b - - 0 1
After the moves g8d8, what is the resulting position?
State needed for full FEN:
Side to move: black
Castling rights: none
En passant: none
Halfmove clock: 0
Fullmove number: 1

Answer format: return exactly "Result FEN: <complete six-field FEN>".


Prompt:
FEN: 8/8/6n1/5k2/3r4/6K1/8/8 b - - 9 72
List the material inventory by side and piece type.

Answer format: return exactly two lines starting "White inventory:" and "Black inventory:".

White inventory: king=g3; queen=none; rook=none; bishop=none; knight=none; pawn=none.
Black inventory: king=f5; queen=none; rook=d4; bishop=none; knight=g6; pawn=none.


Prompt:
FEN: r2qk2r/ppp1bppp/2np1n2/4pb2/2P5/1PN2NP1/PB1PPPBP/R2QK2R b KQkq - 4 7
Count each piece type for both sides.

Answer format: return exactly two lines starting "White counts:" and "Black counts:".

White counts: king=1; queen=1; rook=2; bishop=2; knight=2; pawn=8.
Black counts: king=1; queen=1; rook=2; bishop=2; knight=2; pawn=8.


Prompt:
FEN: 3n4/kbBR2R1/p5K1/1p1p2r1/2pP2P1/P1P5/1P5P/8 w - - 5 42
Convert the piece counts into material value totals.

Answer format: return exactly two lines starting "White values:" and "Black values:".

White values: king=0; queen=0; rook=10; bishop=3; knight=0; pawn=6; total=19.
Black values: king=0; queen=0; rook=5; bishop=3; knight=3; pawn=4; total=15.


Prompt:
FEN: r1bqr1k1/ppp2ppp/2p2n2/2b1p3/2N1P3/3P1N2/PPP1QPPP/R1B1K2R b KQ -
Trace inventory, counts, values, and material balance.

Answer format: return exactly four lines starting "Inventory:", "Counts:", "Values:", and "Balance:".

Inventory: white king=e1; queen=e2; rook=a1,h1; bishop=c1; knight=f3,c4; pawn=a2,b2,c2,f2,g2,h2,d3,e4 | black king=g8; queen=d8; rook=a8,e8; bishop=c5,c8; knight=f6; pawn=e5,c6,a7,b7,c7,f7,g7,h7
Counts: white king=1; queen=1; rook=2; bishop=1; knight=2; pawn=8 | black king=1; queen=1; rook=2; bishop=2; knight=1; pawn=8
Values: white total=36; black total=36
Balance: Material is equal.


Prompt:
Starting FEN: 2k4r/p1p2ppp/2pb4/5b2/1P6/1Nn2P2/P4KPP/R1N4R w - - 0 1
After the moves c1e2 c3d5 h2h3, what is the resulting position?
State needed for full FEN:
Side to move: white
Castling rights: none
En passant: none
Halfmove clock: 0
Fullmove number: 1

Answer format: return exactly "Result FEN: <complete six-field FEN>".

Result FEN: 2k4r/p1p2ppp/2pb4/3n1b2/1P6/1N3P1P/P3NKP1/R6R b - - 0 2


Prompt:
Position (FEN): 2kr1b1r/pb4pp/1pp1p3/8/2N1p3/1P2P3/P1Q1B1PP/q3K2R w K - 0 19
Show me the board.


Prompt:
Here is the current board:
8 r . . q . r k .
7 . p . . n p p p
6 . p . . . n . .
5 p P . . p . B .
4 P . . . P . . .
3 . . P . . Q . P
2 . . . . N P P .
1 R . . . . R K .
  a b c d e f g h
Write the FEN for this position.
State needed for full FEN:
Side to move: black
Castling rights: none
En passant: none
Halfmove clock: 2
Fullmove number: 16

Answer format: return exactly one complete six-field FEN, with no prefix and no explanation.


Prompt:
FEN: 5r2/8/1nk1p1N1/p2p2Np/Pn1R3P/5P2/5KP1/8 b - -
What piece is on c6?

Answer format: for a square query, return only the piece name or empty; do not include the square. For a locate query, return only space-separated squares.


Prompt:
FEN: 5k2/p1p1q2p/1p2bp2/nP5N/2p5/2Q5/P4PPP/3R2K1 w - -
What is the material count for both sides?

White (9 pieces): 1 king, 1 knight, 5 pawns, 1 queen, 1 rook. Black (10 pieces): 1 bishop, 1 king, 1 knight, 6 pawns, 1 queen. White is up 1 point(s) of material.


Prompt:
FEN: rnbqk1nr/5ppp/2p1p3/pp6/PbpPP3/2N5/1P1B1PPP/R2QKBNR w KQkq -
What is on h1?

Answer format: return exactly "<square>=<piece>" or "<square>=empty".


Prompt:
FEN: 8/p5p1/1p1k1b2/3P4/1R4P1/8/P6P/5K2 w - -
What is the compressed FEN row for rank 8?

Answer format: return exactly "rank N: <compressed FEN row>".


Prompt:
FEN: 4r1k1/1pp2pp1/3q3p/p3n3/2Pp4/P2Q1N2/1P3PPP/R5K1 w - - 1 20
For square d5, give the FEN row-from-top and file index.

Answer format: return exactly "<square>: file=<file>; rank=<rank>; fen_row_from_top=<1-8>; file_index=<1-8>".

d5: file=d; rank=5; fen_row_from_top=4; file_index=4


Prompt:
FEN: r3k2r/1b1qb1pp/p7/1p1n1P2/2p5/2P3N1/PPBBQPPP/3RR1K1 w kq - 4 19
Compressed rank 5 row: 1p1n1P2
Expand it into file cells a through h.

Answer format: return exactly "rank N: a=<cell>; b=<cell>; ...; h=<cell>".


Prompt:
Rank 2 row before: 1P3P2
File h changes from 1 to K. Rewrite the compressed row.

Answer format: return exactly "rank N: <before-row> -> <after-row>".


Prompt:
Board FEN before: 8/1b2kP2/5R2/8/8/8/8/5K2
Apply square edits: e7 k->1; d8 1->k
Return the resulting board FEN only.

Answer format: return exactly "Result board FEN: <piece-placement-field>".


Prompt:
Starting FEN: r1bqk2r/pp1nbppp/2p5/8/3NB3/7P/PPP2PP1/R1BQ1RK1 b kq -
Move: c6c5
List the square lookups and rank edits.

Answer format: return exactly three lines starting "Lookup:", "Squares:", and "Ranks:"; do not include Result FEN.

Lookup: c6=black pawn; c5=empty.
Squares: c6 black pawn->empty; c5 empty->black pawn.
Ranks: rank 6 c p->1; rank 5 c 1->p.


Prompt:
Starting FEN: 2r1k2r/pp1bnppp/1q2p3/2b1P3/N2p4/3BBP2/PP3P1P/1R1QR1K1 b k - 0 1
Move: f7f5
Use square lookups and rank edits to assemble the resulting full FEN.
State needed for full FEN:
Side to move: black
Castling rights: k
En passant: none
Halfmove clock: 0
Fullmove number: 1

Answer format: include the edit trace and exactly one final line "Result FEN: <complete six-field FEN>".

Move 1: black pawn f7f5.
Lookup: f7=black pawn; f5=empty.
Squares: f7 black pawn->empty; f5 empty->black pawn.
Ranks: rank 7 f p->1; rank 5 f 1->p.
Result FEN: 2r1k2r/pp1bn1pp/1q2p3/2b1Pp2/N2p4/3BBP2/PP3P1P/1R1QR1K1 w k f6 0 2


Prompt:
Starting FEN: R7/p5pk/2p4p/2r1prn1/P2p4/3P3P/5PPN/4R1K1 b - - 3 32
Move: g5f3
Rewrite the affected compressed FEN rank rows and give Result FEN.
State needed for full FEN:
Side to move: black
Castling rights: none
En passant: none
Halfmove clock: 3
Fullmove number: 32

Answer format: first line starts "Rows:" and final line is "Result FEN: <complete six-field FEN>".

Rows: rank 5 2r1prn1->2r1pr2; rank 3 3P3P->3P1n1P.
Result FEN: R7/p5pk/2p4p/2r1pr2/P2p4/3P1n1P/5PPN/4R1K1 w - - 4 33


Prompt:
Starting FEN: r1b2r1k/4qp1p/p1n1pb1Q/4pP2/1p2N3/8/PPP4P/2KR1BR1 b - - 0 1
After the moves e7c7, what is the resulting position?
State needed for full FEN:
Side to move: black
Castling rights: none
En passant: none
Halfmove clock: 0
Fullmove number: 1

Answer format: return exactly "Result FEN: <complete six-field FEN>".

Result FEN: r1b2r1k/2q2p1p/p1n1pb1Q/4pP2/1p2N3/8/PPP4P/2KR1BR1 w - - 1 2


Prompt:
FEN: r2b1q1r/1k1R1n2/1p2pP1p/7Q/p3N2P/4P1B1/1P2N2R/2K5 b - - 1 33
List the material inventory by side and piece type.

Answer format: return exactly two lines starting "White inventory:" and "Black inventory:".

White inventory: king=c1; queen=h5; rook=h2,d7; bishop=g3; knight=e2,e4; pawn=b2,e3,h4,f6.
Black inventory: king=b7; queen=f8; rook=a8,h8; bishop=d8; knight=f7; pawn=a4,b6,e6,h6.


Prompt:
FEN: 5rk1/p1q1bpp1/2p1p1p1/2Pp2P1/3PnP2/4P2P/P3Q3/R3R1K1 b - - 0 23
Count each piece type for both sides.

Answer format: return exactly two lines starting "White counts:" and "Black counts:".

White counts: king=1; queen=1; rook=2; bishop=0; knight=0; pawn=7.
Black counts: king=1; queen=1; rook=1; bishop=1; knight=1; pawn=7.


Prompt:
FEN: 5rk1/2p3pp/2p2p1n/pp2p3/4P2q/PP5Q/2P2PP1/R3R1K1 b - - 0 21
Convert the piece counts into material value totals.

Answer format: return exactly two lines starting "White values:" and "Black values:".

White values: king=0; queen=9; rook=10; bishop=0; knight=0; pawn=6; total=25.
Black values: king=0; queen=9; rook=5; bishop=0; knight=3; pawn=8; total=25.


Prompt:
FEN: r5k1/pp3ppp/2p5/3n2q1/P7/1P1P1BPb/5P1P/R2QR1K1 b - - 0 20
Trace inventory, counts, values, and material balance.

Answer format: return exactly four lines starting "Inventory:", "Counts:", "Values:", and "Balance:".

Inventory: white king=g1; queen=d1; rook=a1,e1; bishop=f3; knight=none; pawn=f2,h2,b3,d3,g3,a4 | black king=g8; queen=g5; rook=a8; bishop=h3; knight=d5; pawn=c6,a7,b7,f7,g7,h7
Counts: white king=1; queen=1; rook=2; bishop=1; knight=0; pawn=6 | black king=1; queen=1; rook=1; bishop=1; knight=1; pawn=6
Values: white total=28; black total=26
Balance: White is up 2 point(s) of material.


Prompt:
Starting FEN: r2qk2r/pp1nbpp1/2pp1np1/8/8/3P1BP1/PPP1Q2P/RNB1K1NR b KQkq - 3 11
After the moves h8h4 e1d1, what is the resulting position?
State needed for full FEN:
Side to move: black
Castling rights: KQkq
En passant: none
Halfmove clock: 3
Fullmove number: 11

Answer format: return exactly "Result FEN: <complete six-field FEN>".

Result FEN: r2qk3/pp1nbpp1/2pp1np1/8/7r/3P1BP1/PPP1Q2P/RNBK2NR b q - 5 12


Prompt:
Position (FEN): 8/6p1/p2N1k1p/1p2n3/1P2K3/P5P1/8/8 b - - 2 45
Show me the board.


Prompt:
Here is the current board:
8 . . . . . . . .
7 . p . . . . k p
6 p . . . . . . .
5 . . . . . r . .
4 . b p . . . . .
3 . . . . . n . P
2 P . . . . P . .
1 . . . . R K . .
  a b c d e f g h
Write the FEN for this position.
State needed for full FEN:
Side to move: black
Castling rights: none
En passant: none
Halfmove clock: 3
Fullmove number: 34

Answer format: return exactly one complete six-field FEN, with no prefix and no explanation.


Prompt:
FEN: r6r/pp2nkpp/3p4/3P2B1/1P1b2Q1/P2P3P/2P3P1/4q2K w - - 1 22
What piece is on g4?

Answer format: for a square query, return only the piece name or empty; do not include the square. For a locate query, return only space-separated squares.


Prompt:
FEN: r1b1k2r/ppp2ppp/2n1pn2/2b5/4P3/2P2N2/PP1N1PPP/R1BBK2R b KQkq -
What is the material count for both sides?

White (14 pieces): 2 bishops, 1 king, 2 knights, 7 pawns, 2 rooks. Black (14 pieces): 2 bishops, 1 king, 2 knights, 7 pawns, 2 rooks. Material is equal.


Prompt:
FEN: rn2kb1r/pp2q1pp/2p5/5B2/8/4nP2/PPP3PP/R3K2R w KQkq - 0 18
What is on e8?

Answer format: return exactly "<square>=<piece>" or "<square>=empty".


Prompt:
FEN: 2r2rk1/1bqn1pp1/pN3b1p/2p5/2P1p3/P2BPN2/1B3PPP/QR3RK1 b - -
What is the compressed FEN row for rank 7?

Answer format: return exactly "rank N: <compressed FEN row>".


Prompt:
FEN: 8/3P2pp/2Br1p2/P4k2/7P/8/4K3/8 b - -
For square d7, give the FEN row-from-top and file index.

Answer format: return exactly "<square>: file=<file>; rank=<rank>; fen_row_from_top=<1-8>; file_index=<1-8>".

d7: file=d; rank=7; fen_row_from_top=2; file_index=4


Prompt:
FEN: r3kb1r/1b3p2/pq1ppP1p/6p1/2P5/1N1Q2B1/Pp3PPP/1K1RR3 b kq -
Compressed rank 6 row: pq1ppP1p
Expand it into file cells a through h.

Answer format: return exactly "rank N: a=<cell>; b=<cell>; ...; h=<cell>".


Prompt:
Rank 1 row before: R3K2R
File a changes from R to 1. Rewrite the compressed row.

Answer format: return exactly "rank N: <before-row> -> <after-row>".


r2qkb1r/1p1b1ppp/p3pn2/2p1N3/8/3P4/PPP2PPP/RNBQR1K1 b kq -

Prompt:
Board FEN before: r2qkb1r/1p1b1ppp/p3pn2/2p1N3/8/3P4/PPP2PPP/RNBQR1K1
Apply square edits: g7 p->1; g6 1->p
Return the resulting board FEN only.

Answer format: return exactly "Result board FEN: <piece-placement-field>".

Result board FEN: r2qkb1r/1p1b1p1p/p3pnp1/2p1N3/8/3P4/PPP2PPP/RNBQR1K1


Prompt:
Starting FEN: 8/8/8/4Nk2/3K4/2Q5/8/8 w - -
Move: c3f3
List the square lookups and rank edits.

Answer format: return exactly three lines starting "Lookup:", "Squares:", and "Ranks:"; do not include Result FEN.

Lookup: c3=white queen; f3=empty.
Squares: c3 white queen->empty; f3 empty->white queen.
Ranks: rank 3 c Q->1; rank 3 f 1->Q.


Prompt:
Starting FEN: 2kr3r/pbpp4/1p2p1n1/7p/3PP3/2NN1q2/PPPQ4/2KR1R2 b - - 1 19
Move: e6e5
Use square lookups and rank edits to assemble the resulting full FEN.
State needed for full FEN:
Side to move: black
Castling rights: none
En passant: none
Halfmove clock: 1
Fullmove number: 19

Answer format: include the edit trace and exactly one final line "Result FEN: <complete six-field FEN>".

Move 1: black pawn e6e5.
Lookup: e6=black pawn; e5=empty.
Squares: e6 black pawn->empty; e5 empty->black pawn.
Ranks: rank 6 e p->1; rank 5 e 1->p.
Result FEN: 2kr3r/pbpp4/1p4n1/4p2p/3PP3/2NN1q2/PPPQ4/2KR1R2 w - - 0 20


Prompt:
Starting FEN: rn1qkb1r/pbp2ppp/1p6/8/3pP3/2P2N2/P1Q2PPP/R1B1KB1R w KQkq - 0 1
Move: c1a3
Rewrite the affected compressed FEN rank rows and give Result FEN.
State needed for full FEN:
Side to move: white
Castling rights: KQkq
En passant: none
Halfmove clock: 0
Fullmove number: 1

Answer format: first line starts "Rows:" and final line is "Result FEN: <complete six-field FEN>".

Rows: rank 1 R1B1KB1R->R3KB1R; rank 3 2P2N2->B1P2N2.
Result FEN: rn1qkb1r/pbp2ppp/1p6/8/3pP3/B1P2N2/P1Q2PPP/R3KB1R b KQkq - 1 1


Prompt:
Starting FEN: r5k1/5pp1/p1q1p3/2b1B1p1/4R3/1P3Q2/P2r1P1P/4R1K1 w - - 2 27
After the moves e1f1, what is the resulting position?
State needed for full FEN:
Side to move: white
Castling rights: none
En passant: none
Halfmove clock: 2
Fullmove number: 27

Answer format: return exactly "Result FEN: <complete six-field FEN>".


Prompt:
FEN: r1br2k1/1p3pbp/pq2p1p1/8/3P4/1P2QN2/P3BPPP/R2R2K1 b - -
List the material inventory by side and piece type.

Answer format: return exactly two lines starting "White inventory:" and "Black inventory:".

White inventory: king=g1; queen=e3; rook=a1,d1; bishop=e2; knight=f3; pawn=a2,f2,g2,h2,b3,d4.
Black inventory: king=g8; queen=b6; rook=a8,d8; bishop=g7,c8; knight=none; pawn=a6,e6,g6,b7,f7,h7.


Prompt:
FEN: rn1qk2r/pb1p1ppp/1p2pn2/2p5/1bPPP3/2NB4/PPQ2PPP/R1B1K1NR w KQkq -
Count each piece type for both sides.

Answer format: return exactly two lines starting "White counts:" and "Black counts:".

White counts: king=1; queen=1; rook=2; bishop=2; knight=2; pawn=8.
Black counts: king=1; queen=1; rook=2; bishop=2; knight=2; pawn=8.


Prompt:
FEN: r1bqkb1r/pp2pp1p/2np1np1/2p5/4P3/1P1P1N1P/PBP2PP1/RN1QKB1R b KQkq - 1 6
Convert the piece counts into material value totals.

Answer format: return exactly two lines starting "White values:" and "Black values:".

White values: king=0; queen=9; rook=10; bishop=6; knight=6; pawn=8; total=39.
Black values: king=0; queen=9; rook=10; bishop=6; knight=6; pawn=8; total=39.


Prompt:
FEN: 8/8/8/4K3/4Q3/8/3p1k2/8 w - -
Trace inventory, counts, values, and material balance.

Answer format: return exactly four lines starting "Inventory:", "Counts:", "Values:", and "Balance:".

Inventory: white king=e5; queen=e4; rook=none; bishop=none; knight=none; pawn=none | black king=f2; queen=none; rook=none; bishop=none; knight=none; pawn=d2
Counts: white king=1; queen=1; rook=0; bishop=0; knight=0; pawn=0 | black king=1; queen=0; rook=0; bishop=0; knight=0; pawn=1
Values: white total=9; black total=1
Balance: White is up 8 point(s) of material.


Prompt:
Starting FEN: 5bk1/5p1p/6pP/1p3rP1/p1b5/P1P1B3/1P1K1R2/8 w - - 0 39
After the moves e3c5 f7f6, what is the resulting position?
State needed for full FEN:
Side to move: white
Castling rights: none
En passant: none
Halfmove clock: 0
Fullmove number: 39

Answer format: return exactly "Result FEN: <complete six-field FEN>".


Prompt:
Position (FEN): 3q1rk1/3n1p2/r2b3p/pRp3p1/2PpP3/3P2B1/P1Q1BPPP/5RK1 b - - 5 23
Show me the board.


Prompt:
Here is the current board:
8 r . b q k . . r
7 p p p p b . p p
6 . . n . . . . .
5 . . . N . . . .
4 . . . p Q . . .
3 . . . . . . . .
2 P P P . . P P P
1 R . B . K B . R
  a b c d e f g h
Write the FEN for this position.
State needed for full FEN:
Side to move: black
Castling rights: KQkq
En passant: none
Halfmove clock: 0
Fullmove number: 1

Answer format: return exactly one complete six-field FEN, with no prefix and no explanation.

r1bqk2r/ppppb1pp/2n5/3N4/3pQ3/8/PPP2PPP/R1B1KB1R b KQkq - 0 1


Prompt:
FEN: 8/5p2/8/5p1k/1p5P/1P3K2/5P2/8 w - -
What piece is on h5?

Answer format: for a square query, return only the piece name or empty; do not include the square. For a locate query, return only space-separated squares.


Prompt:
FEN: rn1qkbnr/p1p2ppp/1p2p3/3p1b2/2PP4/1Q3N2/PP2PPPP/RNB1KB1R b KQkq -
What is the material count for both sides?

White (16 pieces): 2 bishops, 1 king, 2 knights, 8 pawns, 1 queen, 2 rooks. Black (16 pieces): 2 bishops, 1 king, 2 knights, 8 pawns, 1 queen, 2 rooks. Material is equal.


Prompt:
FEN: r6r/ppk1q1bp/2pp1p1n/4p1pB/4P3/2PP1Q2/PP3PPP/R1B2RK1 w - - 2 23
What is on h7?

Answer format: return exactly "<square>=<piece>" or "<square>=empty".


Prompt:
FEN: rn2k1nr/1pp2ppp/p7/4qN2/3N4/7P/PPPQBPP1/R3K2R w KQkq - 2 15
What is the compressed FEN row for rank 3?

Answer format: return exactly "rank N: <compressed FEN row>".


Prompt:
FEN: 8/1pp2k2/p2p4/5p1p/PbP1K3/1P4P1/1B6/8 w - - 0 36
For square c2, give the FEN row-from-top and file index.

Answer format: return exactly "<square>: file=<file>; rank=<rank>; fen_row_from_top=<1-8>; file_index=<1-8>".

c2: file=c; rank=2; fen_row_from_top=7; file_index=3


Prompt:
FEN: 2kr2nr/pbpqb1pp/1p2p3/5p2/3P4/2N3N1/PPP1QPPP/R1B2RK1 b - - 3 11
Compressed rank 8 row: 2kr2nr
Expand it into file cells a through h.

Answer format: return exactly "rank N: a=<cell>; b=<cell>; ...; h=<cell>".


Prompt:
Rank 8 row before: 2b2qkr
File f changes from q to 1. Rewrite the compressed row.

Answer format: return exactly "rank N: <before-row> -> <after-row>".


Prompt:
Board FEN before: 1k4rr/1pp2p2/pb6/3Pp3/4P1p1/1P2PB2/P3R1P1/2R1K3
Apply square edits: e2 R->1; d2 1->R
Return the resulting board FEN only.

Answer format: return exactly "Result board FEN: <piece-placement-field>".

Result board FEN: 1k4rr/1pp2p2/pb6/3Pp3/4P1p1/1P2PB2/P2R2P1/2R1K3


Prompt:
Starting FEN: 2kr3r/pp3ppp/8/4R3/1b6/2P5/P1Pq1PPP/R5K1 w - - 0 18
Move: e5c5
List the square lookups and rank edits.

Answer format: return exactly three lines starting "Lookup:", "Squares:", and "Ranks:"; do not include Result FEN.

Lookup: e5=white rook; c5=empty.
Squares: e5 white rook->empty; c5 empty->white rook.
Ranks: rank 5 e R->1; rank 5 c 1->R.


Prompt:
Starting FEN: 4r3/1p6/pR2P3/P7/1PpBK3/1k1n4/8/8 b - - 0 1
Move: b3a2
Use square lookups and rank edits to assemble the resulting full FEN.
State needed for full FEN:
Side to move: black
Castling rights: none
En passant: none
Halfmove clock: 0
Fullmove number: 1

Answer format: include the edit trace and exactly one final line "Result FEN: <complete six-field FEN>".

Move 1: black king b3a2.
Lookup: b3=black king; a2=empty.
Squares: b3 black king->empty; a2 empty->black king.
Ranks: rank 3 b k->1; rank 2 a 1->k.
Result FEN: 4r3/1p6/pR2P3/P7/1PpBK3/3n4/k7/8 w - - 1 2


Prompt:
Starting FEN: 7r/1p6/pPp5/P1Pp1pk1/3P3p/4P2K/8/4B3 w - - 1 43
Move: e1c3
Rewrite the affected compressed FEN rank rows and give Result FEN.
State needed for full FEN:
Side to move: white
Castling rights: none
En passant: none
Halfmove clock: 1
Fullmove number: 43

Answer format: first line starts "Rows:" and final line is "Result FEN: <complete six-field FEN>".


Prompt:
Starting FEN: 7r/pp3k2/2b2P2/2bNp3/4P3/P6r/1PPR3P/5R1K b - - 2 30
After the moves c5b6, what is the resulting position?
State needed for full FEN:
Side to move: black
Castling rights: none
En passant: none
Halfmove clock: 2
Fullmove number: 30

Answer format: return exactly "Result FEN: <complete six-field FEN>".

Result FEN: 7r/pp3k2/1bb2P2/3Np3/4P3/P6r/1PPR3P/5R1K w - - 3 31


Prompt:
FEN: 8/7p/1pbp1kp1/p2p1p2/3P1K2/3B4/PPP2PPP/8 w - - 0 29
List the material inventory by side and piece type.

Answer format: return exactly two lines starting "White inventory:" and "Black inventory:".

White inventory: king=f4; queen=none; rook=none; bishop=d3; knight=none; pawn=a2,b2,c2,f2,g2,h2,d4.
Black inventory: king=f6; queen=none; rook=none; bishop=c6; knight=none; pawn=a5,d5,f5,b6,d6,g6,h7.


Prompt:
FEN: rnb3k1/ppp3pp/3bp3/3P4/8/3QB1P1/PPP1N1P1/2K2q2 w - - 0 15
Count each piece type for both sides.

Answer format: return exactly two lines starting "White counts:" and "Black counts:".

White counts: king=1; queen=1; rook=0; bishop=1; knight=1; pawn=6.
Black counts: king=1; queen=1; rook=1; bishop=2; knight=1; pawn=6.


Prompt:
FEN: rn2kbnr/pbpp2q1/1p2pp2/3P2pp/2B1P3/2N2N1P/PPP2PP1/R1BQ1RK1 w kq - 2 9
Convert the piece counts into material value totals.

Answer format: return exactly two lines starting "White values:" and "Black values:".

White values: king=0; queen=9; rook=10; bishop=6; knight=6; pawn=8; total=39.
Black values: king=0; queen=9; rook=10; bishop=6; knight=6; pawn=8; total=39.


Prompt:
FEN: 4r1k1/5pp1/2p2q2/1p1p3p/1P1P1N2/4r1PN/2Q2K2/1R6 w - -
Trace inventory, counts, values, and material balance.

Answer format: return exactly four lines starting "Inventory:", "Counts:", "Values:", and "Balance:".

Inventory: white king=f2; queen=c2; rook=b1; bishop=none; knight=h3,f4; pawn=g3,b4,d4 | black king=g8; queen=f6; rook=e3,e8; bishop=none; knight=none; pawn=b5,d5,h5,c6,f7,g7
Counts: white king=1; queen=1; rook=1; bishop=0; knight=2; pawn=3 | black king=1; queen=1; rook=2; bishop=0; knight=0; pawn=6
Values: white total=23; black total=25
Balance: Black is up 2 point(s) of material.


Prompt:
Starting FEN: 2q3k1/6p1/1Q1Prp1p/2p5/8/1P4BP/1PP2PPK/8 b - - 0 36
After the moves e6e3 b6a7, what is the resulting position?
State needed for full FEN:
Side to move: black
Castling rights: none
En passant: none
Halfmove clock: 0
Fullmove number: 36

Answer format: return exactly "Result FEN: <complete six-field FEN>".