Prompt:
FEN: r3kb1r/ppp1qppp/2n1bn2/8/2BP4/5N2/PP3PPP/RNBQR1K1 b kq -
Compressed rank 6 row: 2n1bn2
Expand it into file cells a through h.

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


Prompt:
Rank 3 row before: 8
File b changes from 1 to q. Rewrite the compressed row.

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


Prompt:
Board FEN before: r6k/pp2N1p1/3p3p/4p3/4P3/3P4/PPPq2rP/1K3R1R
Apply square edits: h2 P->1; h4 1->P
Return the resulting board FEN only.

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

Result board FEN: r6k/pp2N1p1/3p3p/4p3/4P2P/3P4/PPPq2r1/1K3R1R


Prompt:
Starting FEN: 7k/Bb4bp/4Bpp1/4p3/P3P3/8/1r5r/R3RK2 b - - 0 26
Move: b2c2
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=black rook; c2=empty.
Squares: b2 black rook->empty; c2 empty->black rook.
Ranks: rank 2 b r->1; rank 2 c 1->r.


Prompt:
Starting FEN: 4k3/1RQ5/P6p/8/4Ppp1/5N1P/2P2PP1/6K1 w - - 0 41
Move: c7c3
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: 41

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

Move 1: white queen c7c3.
Lookup: c7=white queen; c3=empty.
Squares: c7 white queen->empty; c3 empty->white queen.
Ranks: rank 7 c Q->1; rank 3 c 1->Q.
Result FEN: 4k3/1R6/P6p/8/4Ppp1/2Q2N1P/2P2PP1/6K1 b - - 1 41


Prompt:
Starting FEN: r2qk1nr/1pp2ppp/p1p5/4b3/4PB2/2N2Q2/PPP2PPP/R3K2R b KQkq - 0 1
Move: e8d7
Rewrite the affected compressed FEN rank rows and give Result FEN.
State needed for full FEN:
Side to move: black
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 8 r2qk1nr->r2q2nr; rank 7 1pp2ppp->1ppk1ppp.
Result FEN: r2q2nr/1ppk1ppp/p1p5/4b3/4PB2/2N2Q2/PPP2PPP/R3K2R w KQ - 1 2


Prompt:
Starting FEN: 4rrk1/ppp3pp/3p4/5pq1/4P3/2NB1P2/PP3K2/5R2 b - - 1 23
After the moves g8f7, 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: 23

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

Result FEN: 4rr2/ppp2kpp/3p4/5pq1/4P3/2NB1P2/PP3K2/5R2 w - - 2 24


Prompt:
FEN: 2r2rk1/3q1pb1/p2p2pp/1ppP4/5P1B/P1P4P/1PQ3P1/R4RK1 b - - 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=c2; rook=a1,f1; bishop=h4; knight=none; pawn=b2,g2,a3,c3,h3,f4,d5.
Black inventory: king=g8; queen=d7; rook=c8,f8; bishop=g7; knight=none; pawn=b5,c5,a6,d6,g6,h6,f7.


Prompt:
FEN: 2kr1b1r/ppq2ppp/2b2n2/4P3/2B5/2P3Q1/PP3PPP/RNB1K2R b KQ -
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=1; pawn=7.
Black counts: king=1; queen=1; rook=2; bishop=2; knight=1; pawn=5.


Prompt:
FEN: 8/8/2K5/p1p3kP/PbP5/1P6/4B3/8 b - - 2 67
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=0; pawn=4; total=7.
Black values: king=0; queen=0; rook=0; bishop=3; knight=0; pawn=2; total=5.


Prompt:
FEN: 8/5k2/N1b1p1p1/1p6/2nP2PP/P7/5K2/2B5 w - - 3 43
Trace inventory, counts, values, and material balance.

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

Inventory: white king=f2; queen=none; rook=none; bishop=c1; knight=a6; pawn=a3,d4,g4,h4 | black king=f7; queen=none; rook=none; bishop=c6; knight=c4; pawn=b5,e6,g6
Counts: white king=1; queen=0; rook=0; bishop=1; knight=1; pawn=4 | black king=1; queen=0; rook=0; bishop=1; knight=1; pawn=3
Values: white total=10; black total=9
Balance: White is up 1 point(s) of material.


Prompt:
Starting FEN: 8/p3r2p/1k6/2n1P3/2p5/R7/P1P4P/3R2K1 w - - 3 35
After the moves h2h4 b6b5, what is the resulting position?
State needed for full FEN:
Side to move: white
Castling rights: none
En passant: none
Halfmove clock: 3
Fullmove number: 35

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


Prompt:
Position (FEN): r3r3/p2b1kpp/2p5/3p4/n6P/5PP1/PP1N1KB1/R3R3 w - -
Show me the board.


Prompt:
Here is the current board:
8 r b . . . r k .
7 . b . n . p p p
6 p . p . . q . .
5 . p . p . . . .
4 . . . . . N . .
3 . P . . P B . 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: none
En passant: none
Halfmove clock: 4
Fullmove number: 19

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


Prompt:
FEN: 8/3P1k2/8/8/B5R1/6P1/5B2/6K1 b - - 0 52
What piece is on f2?

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: rnbqk2r/ppp2ppp/8/8/8/2N2N2/PPPPPK2/R1BQ1B2 b kq -
What is the material count for both sides?

White (12 pieces): 2 bishops, 1 king, 2 knights, 5 pawns, 1 queen, 1 rook. Black (12 pieces): 1 bishop, 1 king, 1 knight, 6 pawns, 1 queen, 2 rooks. Material is equal.


Prompt:
FEN: r1bqk2r/pp1pnppp/1bn5/4p3/3PP3/B1P2N2/P4PPP/RN1QKB1R b KQkq -
What is on b2?

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


Prompt:
FEN: 1rbq1rk1/4nppp/p2p4/1p1Np1b1/4P3/2P5/PPN1BPPP/R2Q1RK1 w - -
What is the compressed FEN row for rank 1?

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


Prompt:
FEN: 8/1p2R3/2k3p1/2P1n1p1/8/2K5/8/8 b - - 0 47
For square e2, 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>".

e2: file=e; rank=2; fen_row_from_top=7; file_index=5


Prompt:
FEN: N7/8/8/2N5/2N1N3/8/5Q1K/k7 b - -
Compressed rank 1 row: k7
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: 5PPP
File f changes from P to 1. Rewrite the compressed row.

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


rn5r/1ppbkppp/p2p1n1q/3Pp3/4P1P1/2N2N1P/PPP1QP2/1K1R1B1R b - - 0 15

Prompt:
Board FEN before: rn5r/1ppbkppp/p2p1n1q/3Pp3/4P1P1/2N2N1P/PPP1QP2/1K1R1B1R
Apply square edits: d7 b->1; b5 1->b
Return the resulting board FEN only.

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

Result board FEN: rn5r/1pp1kppp/p2p1n1q/1b1Pp3/4P1P1/2N2N1P/PPP1QP2/1K1R1B1R


Prompt:
Starting FEN: rn1q1rk1/2p2ppp/pp1bp3/8/1PBPb3/P3PN2/1B3PPP/R2Q1RK1 w - - 0 12
Move: f3g5
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 knight; g5=empty.
Squares: f3 white knight->empty; g5 empty->white knight.
Ranks: rank 3 f N->1; rank 5 g 1->N.


Prompt:
Starting FEN: 8/8/8/4nRk1/6P1/6KP/8/8 b - - 16 57
Move: g5g6
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: 16
Fullmove number: 57

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

Move 1: black king g5g6.
Lookup: g5=black king; g6=empty.
Squares: g5 black king->empty; g6 empty->black king.
Ranks: rank 5 g k->1; rank 6 g 1->k.
Result FEN: 8/8/6k1/4nR2/6P1/6KP/8/8 w - - 17 58


Prompt:
Starting FEN: 1r6/5pk1/1rpp4/p3p1pq/1bP1P3/1B1P1N2/RP2QP2/5K2 w - - 0 38
Move: f1g1
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: 38

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

Rows: rank 1 5K2->6K1.
Result FEN: 1r6/5pk1/1rpp4/p3p1pq/1bP1P3/1B1P1N2/RP2QP2/6K1 b - - 1 38


Prompt:
Starting FEN: r1bqk1nr/1ppp1ppp/p1n5/2bNp3/4P3/P4P2/1PPP2PP/R1BQKBNR w KQkq - 0 6
After the moves a1b1, what is the resulting position?
State needed for full FEN:
Side to move: white
Castling rights: KQkq
En passant: none
Halfmove clock: 0
Fullmove number: 6

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

Result FEN: r1bqk1nr/1ppp1ppp/p1n5/2bNp3/4P3/P4P2/1PPP2PP/1RBQKBNR b Kkq - 1 6


Prompt:
FEN: r5k1/pp4pp/4Np2/3n4/P6B/8/1r3PPK/R1R5 w - - 2 25
List the material inventory by side and piece type.

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

White inventory: king=h2; queen=none; rook=a1,c1; bishop=h4; knight=e6; pawn=f2,g2,a4.
Black inventory: king=g8; queen=none; rook=b2,a8; bishop=none; knight=d5; pawn=f6,a7,b7,g7,h7.


Prompt:
FEN: r5k1/p4p1p/1p6/5q2/3Qp3/P4N2/1PP1PK2/R4B1b w - - 2 25
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=1; knight=1; pawn=4.
Black counts: king=1; queen=1; rook=1; bishop=1; knight=0; pawn=5.


Prompt:
FEN: 8/p1k3N1/1pn2N1p/4p1p1/8/4P3/PP3PPP/3R2K1 w - - 1 33
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=5; bishop=0; knight=6; pawn=6; total=17.
Black values: king=0; queen=0; rook=0; bishop=0; knight=3; pawn=5; total=8.


Prompt:
FEN: rn1qkbnr/1b1p1pp1/p3p2p/1pp5/4P3/P2P1Q2/BPP2PPP/RNB1K1NR w KQkq - 0 7
Trace inventory, counts, values, and material balance.

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

Inventory: white king=e1; queen=f3; rook=a1,h1; bishop=c1,a2; knight=b1,g1; pawn=b2,c2,f2,g2,h2,a3,d3,e4 | black king=e8; queen=d8; rook=a8,h8; bishop=b7,f8; knight=b8,g8; pawn=b5,c5,a6,e6,h6,d7,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: r4rk1/1p1nqppp/1bp2n2/p3p3/1PN1P3/P4BPP/2P2PK1/R1B1QR2 b - - 0 1
After the moves b6e3 e1e3, 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: r4rk1/1p1nqppp/2p2n2/p3p3/1PN1P3/P3QBPP/2P2PK1/R1B2R2 b - - 0 2


Prompt:
Position (FEN): k3N1r1/pb2n1b1/1p3n1p/3pQ3/P2Pp3/1P2P1PB/3N3P/R4RK1 w - - 1 28
Show me the board.


Prompt:
Here is the current board:
8 r n . q k . . r
7 . p . . b p p .
6 p . . p b n . .
5 . . . . p . B .
4 . . . . P . . .
3 . N N . . Q . P
2 P P P . . P . .
1 R . . . 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.

rn1qk2r/1p2bpp1/p2pbn2/4p1B1/4P3/1NN2Q1P/PPP2P2/R3KB1R b KQkq - 0 1


Prompt:
FEN: 8/kp6/p1p5/2P2p2/8/P1PB1Pn1/1PK5/8 b - - 1 36
What piece is on b7?

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: r4r2/p2k2pp/R1p3p1/4P3/1P6/2N4P/5PP1/5RK1 b - - 0 26
What is the material count for both sides?

White (9 pieces): 1 king, 1 knight, 5 pawns, 2 rooks. Black (8 pieces): 1 king, 5 pawns, 2 rooks. White is up 3 point(s) of material.


Prompt:
FEN: 8/1p3pp1/p6p/1k1p4/1PBP4/P4P2/4K1PP/8 b - - 0 31
What is on d5?

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


Prompt:
FEN: 8/8/5kB1/ppb1pPp1/7p/1PPK1P1P/8/8 w - - 2 45
What is the compressed FEN row for rank 2?

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


Prompt:
FEN: 3r1rk1/1pN1nppp/p2pb2n/4p3/1PP1P2q/3Q4/P1N1BPPP/2R2RK1 w - -
For square e3, 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>".

e3: file=e; rank=3; fen_row_from_top=6; file_index=5


Prompt:
FEN: r1bqnrk1/ppp2pbp/1n1p2p1/3Pp3/2P1P1P1/2N1BN1P/PP2BP2/R2QK2R b KQ -
Compressed rank 5 row: 3Pp3
Expand it into file cells a through h.

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


r2qkb1r/pp2pppp/2n5/2ppP3/3P2b1/2P2N2/P1P1BPPP/R1BQ1RK1 w kq -

Prompt:
Rank 3 row before: 2P2N2
File f changes from N to 1. Rewrite the compressed row.

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


rnbq1rk1/pp2ppbp/3p2p1/3pP3/3P1P2/3B1N2/PPP3PP/R1BQK2R w KQ -

Prompt:
Board FEN before: rnbq1rk1/pp2ppbp/3p2p1/3pP3/3P1P2/3B1N2/PPP3PP/R1BQK2R
Apply square edits: d1 Q->1; d2 1->Q
Return the resulting board FEN only.

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

Result board FEN: rnbq1rk1/pp2ppbp/3p2p1/3pP3/3P1P2/3B1N2/PPPQ2PP/R1B1K2R


Prompt:
Starting FEN: 2b1k2r/1p1pb1pp/2r1p3/p4p2/1nP2B2/3nPN2/PP2KPPP/R2Q3R b k - 1 17
Move: h7h5
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; h5=empty.
Squares: h7 black pawn->empty; h5 empty->black pawn.
Ranks: rank 7 h p->1; rank 5 h 1->p.


Prompt:
Starting FEN: 8/1k3ppp/8/8/8/8/P4PPP/K7 w - - 0 1
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: 1

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: 8/1k3ppp/8/8/7P/8/P4PP1/K7 b - - 0 1


Prompt:
Starting FEN: 8/3k4/4R3/4pK2/4P3/r3P3/8/8 w - - 0 1
Move: e6c6
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: r1b1kbnr/ppppqppp/8/n7/2B1Pp2/2N2N2/PPPP2PP/R1BQK2R w KQkq - 0 1
After the moves c4b5, what is the resulting 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 "Result FEN: <complete six-field FEN>".

Result FEN: r1b1kbnr/ppppqppp/8/nB6/4Pp2/2N2N2/PPPP2PP/R1BQK2R b KQkq - 1 1


Prompt:
FEN: r1bq1rk1/b3np2/2pp1p1p/p3p3/3PP3/P1P2N1P/1B2BPP1/1R1Q1RK1 b - - 0 16
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=b1,f1; bishop=b2,e2; knight=f3; pawn=f2,g2,a3,c3,h3,d4,e4.
Black inventory: king=g8; queen=d8; rook=a8,f8; bishop=a7,c8; knight=e7; pawn=a5,e5,c6,d6,f6,h6,f7.


Prompt:
FEN: 6k1/5p1p/2N1p1p1/8/p7/5B2/P2r1PPP/R5K1 w - - 0 32
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=1; knight=1; pawn=4.
Black counts: king=1; queen=0; rook=1; bishop=0; knight=0; pawn=5.


Prompt:
FEN: rnbq1rk1/ppp1ppbp/1n4p1/8/2BP4/1PN1PN2/P4PPP/R1BQK2R b 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=7; total=38.
Black values: king=0; queen=9; rook=10; bishop=6; knight=6; pawn=7; total=38.


Prompt:
FEN: r1r3k1/6p1/p1nb1p1p/1p6/1P1NP3/P4P1P/1R3P2/3R2K1 b - - 1 28
Trace inventory, counts, values, and material balance.

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

Inventory: white king=g1; queen=none; rook=d1,b2; bishop=none; knight=d4; pawn=f2,a3,f3,h3,b4,e4 | black king=g8; queen=none; rook=a8,c8; bishop=d6; knight=c6; pawn=b5,a6,f6,h6,g7
Counts: white king=1; queen=0; rook=2; bishop=0; knight=1; pawn=6 | black king=1; queen=0; rook=2; bishop=1; knight=1; pawn=5
Values: white total=19; black total=21
Balance: Black is up 2 point(s) of material.


Prompt:
Starting FEN: rn1qkb1r/pp3ppp/4pn2/2Pp1b2/5P2/4BNP1/PPP1P2P/RN1QKB1R b KQkq - 0 1
After the moves d8c8 d1d2, 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: rnq1kb1r/pp3ppp/4pn2/2Pp1b2/5P2/4BNP1/PPPQP2P/RN2KB1R b KQkq - 2 2


Prompt:
Position (FEN): r1bq1rk1/ppp1bppp/2n5/3np3/2B5/2PP1N1P/PP3PP1/RNBQ1RK1 b - - 1 8
Show me the board.


Prompt:
Here is the current board:
8 r . . . . r k .
7 p p . . b p p p
6 . q . . p n . .
5 . . n p . . . .
4 . . . . . B . .
3 . P . P P N . P
2 P . Q 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: white
Castling rights: none
En passant: none
Halfmove clock: 0
Fullmove number: 13

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


Prompt:
FEN: rn1q1rk1/1pp1bppp/p3pn2/3b4/P1QP4/5NP1/1P1NPPBP/R1B2RK1 w - -
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: r3k2r/1bqnbppp/p2ppn2/3N2B1/1p1NPP2/3B2Q1/PPP3PP/2KRR3 b kq -
What is the material count for both sides?

White (15 pieces): 2 bishops, 1 king, 2 knights, 7 pawns, 1 queen, 2 rooks. Black (15 pieces): 2 bishops, 1 king, 2 knights, 7 pawns, 1 queen, 2 rooks. Material is equal.


Prompt:
FEN: rnb1k2r/pp2ppbp/6p1/q1p5/3PP3/2P1B3/P2Q1PPP/1R2KBNR b Kkq -
What is on b3?

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


Prompt:
FEN: r1bq1rk1/pp2bppp/3p1nn1/2p5/3NPP2/2N1B3/PPP1B1PP/R2Q1RK1 w - - 0 11
What is the compressed FEN row for rank 1?

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


Prompt:
FEN: r1b1kb1r/p1q1pppp/1pn2n2/3p4/3P4/2PB1N1P/PP3PP1/RNBQK2R w KQkq -
For square h3, 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>".

h3: file=h; rank=3; fen_row_from_top=6; file_index=8


Prompt:
FEN: 8/8/8/8/pk6/n1p5/2K5/8 w - - 6 72
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>".


Prompt:
Rank 6 row before: 1p6
File d changes from 1 to Q. Rewrite the compressed row.

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


r1bqkb1r/ppp2ppp/3p1n2/8/2BQP3/2N5/PPP2PPP/R1B1K2R b KQkq - 3 7

Prompt:
Board FEN before: r1bqkb1r/ppp2ppp/3p1n2/8/2BQP3/2N5/PPP2PPP/R1B1K2R
Apply square edits: h8 r->1; g8 1->r
Return the resulting board FEN only.

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

Result board FEN: r1bqkbr1/ppp2ppp/3p1n2/8/2BQP3/2N5/PPP2PPP/R1B1K2R


Prompt:
Starting FEN: 2R5/1Q6/4k3/8/8/4K3/8/8 w - -
Move: b7d5
List the square lookups and rank edits.

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

Lookup: b7=white queen; d5=empty.
Squares: b7 white queen->empty; d5 empty->white queen.
Ranks: rank 7 b Q->1; rank 5 d 1->Q.


Prompt:
Starting FEN: r1bqk1nr/ppp2ppp/4p3/3Pp3/1bP1P3/2N5/PP3PPP/R2QKBNR b KQkq - 0 7
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: KQkq
En passant: none
Halfmove clock: 0
Fullmove number: 7

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: r1bqk1nr/ppp3pp/4p3/3Ppp2/1bP1P3/2N5/PP3PPP/R2QKBNR w KQkq - 0 8


Prompt:
Starting FEN: 8/8/6p1/R5N1/3k4/3n1K2/8/8 w - - 0 1
Move: g5e4
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: rnbqk2r/p3n1b1/2p1p1pp/1p1p1p2/3P4/4P3/PPP1BPPP/RNBQK1NR b KQkq - 1 10
After the moves c8d7, what is the resulting position?
State needed for full FEN:
Side to move: black
Castling rights: KQkq
En passant: none
Halfmove clock: 1
Fullmove number: 10

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

Result FEN: rn1qk2r/p2bn1b1/2p1p1pp/1p1p1p2/3P4/4P3/PPP1BPPP/RNBQK1NR w KQkq - 2 11


Prompt:
FEN: 2r5/p4pkp/2Q3p1/5p2/6P1/8/P6P/5R1K b - - 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=h1; queen=c6; rook=f1; bishop=none; knight=none; pawn=a2,h2,g4.
Black inventory: king=g7; queen=none; rook=c8; bishop=none; knight=none; pawn=f5,g6,a7,f7,h7.


Prompt:
FEN: r4rk1/1pq2p1p/p5p1/8/BPn1Q3/P1P4P/4R1RP/6K1 b - - 2 24
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: r1bq1rk1/pp3ppp/2np1n2/1B2p3/Qb2P3/2N2N2/PPPB1PPP/2KR3R b - - 3 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=7; total=38.
Black values: king=0; queen=9; rook=10; bishop=6; knight=6; pawn=7; total=38.


Prompt:
FEN: 6k1/1p3pb1/1n1p2pp/3Pp3/1P2P3/2r3PP/5P2/1R3BK1 w - - 2 29
Trace inventory, counts, values, and material balance.

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

Inventory: white king=g1; queen=none; rook=b1; bishop=f1; knight=none; pawn=f2,g3,h3,b4,e4,d5 | black king=g8; queen=none; rook=c3; bishop=g7; knight=b6; pawn=e5,d6,g6,h6,b7,f7
Counts: white king=1; queen=0; rook=1; bishop=1; knight=0; pawn=6 | black king=1; queen=0; rook=1; bishop=1; knight=1; pawn=6
Values: white total=14; black total=17
Balance: Black is up 3 point(s) of material.


Prompt:
Starting FEN: 2r2rk1/ppq2ppp/2n1bb2/3p4/1P6/P3P1P1/1BN2PBP/1R1Q1RK1 b - - 2 16
After the moves c7e7 b1a1 e7c7, 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: 16

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

Result FEN: 2r2rk1/ppq2ppp/2n1bb2/3p4/1P6/P3P1P1/1BN2PBP/R2Q1RK1 w - - 5 18


Prompt:
Position (FEN): 3q1rk1/5ppp/2p1p3/1pPn4/1P1P4/r1B3Q1/5PPP/2R1R1K1 b - - 4 24
Show me the board.


Prompt:
Here is the current board:
8 . . . . . . . .
7 . p . . . . p k
6 . . . . . . . p
5 . . . . . . . P
4 . q . . . . 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: 0
Fullmove number: 41

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


Prompt:
FEN: 8/8/5Q2/8/3K4/6k1/8/1b6 b - -
What piece is on d4?

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: r2q1rk1/p2nnppp/2pb4/4p3/2BPP3/1QP2P2/PP5P/RNB1K1R1 b Q -
What is the material count for both sides?

White (14 pieces): 2 bishops, 1 king, 1 knight, 7 pawns, 1 queen, 2 rooks. Black (13 pieces): 1 bishop, 1 king, 2 knights, 6 pawns, 1 queen, 2 rooks. White is up 1 point(s) of material.


Prompt:
FEN: r1bq1rk1/3pbpp1/p1p1p2p/2pnP1NQ/5P2/3P4/PPP3PP/RNB2RK1 w - - 2 11
What is on h7?

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


Prompt:
FEN: r1q2rk1/pppbbp2/2np3p/8/2PPP3/4nNP1/PP2N1B1/R2QR1K1 w - - 0 20
What is the compressed FEN row for rank 8?

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


Prompt:
FEN: rn1qkb1r/pp1n1pp1/2p1p1b1/3p2Pp/3P1B1P/2N1PP1N/PPP5/R2QKB1R b KQkq -
For square h5, 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>".

h5: file=h; rank=5; fen_row_from_top=4; file_index=8


Prompt:
FEN: r3kb1r/ppqbnpp1/1n2p2p/3pP3/3P1PPP/1PPB1N2/3B4/RN1QK2R w KQkq - 5 13
Compressed rank 6 row: 1n2p2p
Expand it into file cells a through h.

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


r3k1nr/ppp1pp1p/6p1/4b3/8/7P/PPP1KPP1/RN5R w kq - 0 12

Prompt:
Rank 1 row before: RN5R
File h changes from R to 1. Rewrite the compressed row.

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


Prompt:
Board FEN before: 1kn5/3Q4/K7/8/8/8/8/8
Apply square edits: c8 n->1; d6 1->n
Return the resulting board FEN only.

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


Prompt:
Starting FEN: r2qk2r/pp1n1ppp/5n2/2bp4/8/3QP3/PP2NPPP/RNB1K2R b KQkq - 4 10
Move: e8g8
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; g8=empty; f8=empty; h8=black rook.
Squares: e8 black king->empty; g8 empty->black king; f8 empty->black rook; h8 black rook->empty.
Ranks: rank 8 e k->1; rank 8 g 1->k; rank 8 f 1->r; rank 8 h r->1.


Prompt:
Starting FEN: r3r1k1/p4ppp/1q1n1n2/1ppp4/8/PPQ1PNP1/2P2PBP/R4RK1 b - - 1 20
Move: f6h5
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: 20

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

Move 1: black knight f6h5.
Lookup: f6=black knight; h5=empty.
Squares: f6 black knight->empty; h5 empty->black knight.
Ranks: rank 6 f n->1; rank 5 h 1->n.
Result FEN: r3r1k1/p4ppp/1q1n4/1ppp3n/8/PPQ1PNP1/2P2PBP/R4RK1 w - - 2 21


Prompt:
Starting FEN: r1bq1rk1/1p2b1pp/p1n1p3/2Pp1p2/1P1Pn3/P4N2/1B2BPPP/RN1Q1RK1 w - - 0 1
Move: a3a4
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 3 P4N2->5N2; rank 4 1P1Pn3->PP1Pn3.
Result FEN: r1bq1rk1/1p2b1pp/p1n1p3/2Pp1p2/PP1Pn3/5N2/1B2BPPP/RN1Q1RK1 b - - 0 1


Prompt:
Starting FEN: rnbq1r2/pppnp1kp/3p2p1/8/3P2PP/2N5/PPPQP3/R3KBNR b KQ - 0 10
After the moves b7b6, 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: 10

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

Result FEN: rnbq1r2/p1pnp1kp/1p1p2p1/8/3P2PP/2N5/PPPQP3/R3KBNR w KQ - 0 11


Prompt:
FEN: 1r1k1bnr/p3q1pp/1p1p1p2/1Bp5/2Pp1P2/BP4PP/P2QPKn1/RN4NR b - - 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=f2; queen=d2; rook=a1,h1; bishop=a3,b5; knight=b1,g1; pawn=a2,e2,b3,g3,h3,c4,f4.
Black inventory: king=d8; queen=e7; rook=b8,h8; bishop=f8; knight=g2,g8; pawn=d4,c5,b6,d6,f6,a7,g7,h7.


Prompt:
FEN: kN6/8/PNK5/8/8/6B1/8/8 b - - 22 76
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=1; knight=2; pawn=1.
Black counts: king=1; queen=0; rook=0; bishop=0; knight=0; pawn=0.


Prompt:
FEN: 8/p7/5pK1/3p3P/P1p1k3/2P2p2/2P5/8 b - - 0 38
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=0; knight=0; pawn=4; total=4.
Black values: king=0; queen=0; rook=0; bishop=0; knight=0; pawn=5; total=5.


Prompt:
FEN: rnbq1rk1/pp3ppp/2pb4/3p4/2PPn3/5N1P/PP2BPP1/RNBQ1RK1 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,f1; bishop=c1,e2; knight=b1,f3; pawn=a2,b2,f2,g2,h3,c4,d4 | black king=g8; queen=d8; rook=a8,f8; bishop=d6,c8; knight=e4,b8; pawn=d5,c6,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=7
Values: white total=38; black total=38
Balance: Material is equal.


Prompt:
Starting FEN: 3R4/1p5r/5pk1/3pbqp1/1P2p3/P3P1PP/5PK1/2R5 w - - 2 35
After the moves d8g8 h7g7 c1g1, 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: 35

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


Prompt:
Position (FEN): N6r/1p3ppp/p1k1p3/4P3/1B1n1P2/1P6/P5PP/5RK1 b - - 0 20
Show me the board.


Prompt:
Here is the current board:
8 . . . . . r . k
7 . p . . q . . p
6 p . n . . p p .
5 . . . p . . . .
4 . . . p . . Q .
3 . . P N . . . P
2 P P . . . 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: 0
Fullmove number: 1

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


Prompt:
FEN: 8/2RQ1pk1/3p1bp1/3P3p/4P3/1P5P/P4PP1/6K1 b - - 3 34
What piece is on h3?

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: 1r4qk/2n5/p2p1RQ1/2pP3P/2P5/8/P5P1/2R1N1K1 w - - 1 32
What is the material count for both sides?

White (10 pieces): 1 king, 1 knight, 5 pawns, 1 queen, 2 rooks. Black (7 pieces): 1 king, 1 knight, 3 pawns, 1 queen, 1 rook. White is up 7 point(s) of material.


Prompt:
FEN: 8/8/1k1K4/4N3/2B5/8/8/8 w - -
What is on b6?

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


Prompt:
FEN: rn1qk2r/pp3ppp/2p1p3/3pN2b/2PPnB2/P1b1P3/1PQ2PPP/R3KB1R w KQkq - 0 10
What is the compressed FEN row for rank 5?

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


Prompt:
FEN: 8/5k2/6p1/5pP1/1R3P1P/5r2/7K/8 w - - 1 37
For square h4, 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>".

h4: file=h; rank=4; fen_row_from_top=5; file_index=8


Prompt:
FEN: 1rb5/p3qpkp/2p1p1p1/2PpP2P/Nr3P2/1P1Q1BP1/P5K1/4R3 b - - 2 29
Compressed rank 1 row: 4R3
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: ppp2ppp
File h changes from p to 1. Rewrite the compressed row.

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


Prompt:
Board FEN before: r2q1r1k/p3np1p/1p2p1p1/3pb3/8/1PPB1Q2/P4PPP/R1B2RK1
Apply square edits: f3 Q->1; g4 1->Q
Return the resulting board FEN only.

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

Result board FEN: r2q1r1k/p3np1p/1p2p1p1/3pb3/6Q1/1PPB4/P4PPP/R1B2RK1


Prompt:
Starting FEN: 1r4k1/RP6/2qPp1p1/3p3p/5r2/8/Q4bPP/1R4K1 w - - 0 30
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: r1bqk2r/pppp1ppp/5n2/2b1p3/B2nP3/2N2N2/PPPP1PPP/R1BQK2R w KQkq - 0 1
Move: a2a3
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: 1

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

Move 1: white pawn a2a3.
Lookup: a2=white pawn; a3=empty.
Squares: a2 white pawn->empty; a3 empty->white pawn.
Ranks: rank 2 a P->1; rank 3 a 1->P.
Result FEN: r1bqk2r/pppp1ppp/5n2/2b1p3/B2nP3/P1N2N2/1PPP1PPP/R1BQK2R b KQkq - 0 1


Prompt:
Starting FEN: 1k6/8/7R/8/Q1P5/1p6/1P6/2K5 b - - 0 43
Move: b8c7
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: 43

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


Prompt:
Starting FEN: 3r2k1/p4p1p/4N3/2p2p2/8/1P2P1P1/r4PBP/1R2K2R b K - 0 22
After the moves a2f2, what is the resulting position?
State needed for full FEN:
Side to move: black
Castling rights: K
En passant: none
Halfmove clock: 0
Fullmove number: 22

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


Prompt:
FEN: 8/p3k2r/3Nb2p/4P1b1/2p5/P1P3R1/1P6/R5K1 w - - 4 38
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=none; rook=a1,g3; bishop=none; knight=d6; pawn=b2,a3,c3,e5.
Black inventory: king=e7; queen=none; rook=h7; bishop=g5,e6; knight=none; pawn=c4,h6,a7.


Prompt:
FEN: 8/8/8/7p/8/6k1/3K4/8 b - - 3 48
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=0.
Black counts: king=1; queen=0; rook=0; bishop=0; knight=0; pawn=1.


Prompt:
FEN: rnbqk2r/pp3ppp/4pb2/3p4/2Pp4/2N1PN2/PP3PPP/R2QKB1R 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=3; knight=6; pawn=7; total=35.
Black values: king=0; queen=9; rook=10; bishop=6; knight=3; pawn=8; total=36.


Prompt:
FEN: r2qkbnr/p1pb1ppp/2pp4/8/4P3/3B4/PPP2PPP/RNBQK2R 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=d1; rook=a1,h1; bishop=c1,d3; knight=b1; pawn=a2,b2,c2,f2,g2,h2,e4 | black king=e8; queen=d8; rook=a8,h8; bishop=d7,f8; knight=g8; pawn=c6,d6,a7,c7,f7,g7,h7
Counts: white king=1; queen=1; rook=2; bishop=2; knight=1; pawn=7 | black king=1; queen=1; rook=2; bishop=2; knight=1; pawn=7
Values: white total=35; black total=35
Balance: Material is equal.


Prompt:
Starting FEN: 8/8/8/2k2p2/P5pp/4K2P/6P1/8 w - - 0 1
After the moves g2g3 g4h3, 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>".


Prompt:
Position (FEN): rnb1k2r/3pn2p/p1p3p1/1p3pP1/2PN1P2/1P1BP3/P5q1/R1BQKR2 w Qkq - 2 17
Show me the board.


rnbq1k1Q/pp1p1p1p/4p1p1/8/2P5/1P2P3/P4PPP/RN2KBNR b KQ - 4 12

Prompt:
Here is the current board:
8 r n b q . k . Q
7 p p . p . p . p
6 . . . . p . p .
5 . . . . . . . .
4 . . P . . . . .
3 . P . . P . . .
2 P . . . . P P P
1 R N . . 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: KQ
En passant: none
Halfmove clock: 4
Fullmove number: 12

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


Prompt:
FEN: 2k1r3/ppp2ppp/2n5/2b2q2/2Q5/2N2pPn/PPPP2BP/R1B2K2 w - - 0 18
What piece is on c5?

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: r2q1rk1/1ppb1pp1/p3pn1p/3pP3/3P4/2PB2PP/PP1N1P2/R2Q1RK1 b - -
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: 1r2kb1r/pb1q1ppp/8/4p3/3p1P2/2N4P/PPP3P1/1RBQ1RK1 w k - 0 15
What is on f2?

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


Prompt:
FEN: r1b2bnr/pppkpppp/8/1N2n3/8/8/PPPP1PPP/R1BQR1K1 w - - 0 11
What is the compressed FEN row for rank 5?

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


Prompt:
FEN: r1b5/pp1pp2k/6pp/4qr2/4N2P/3Q4/PPP2PP1/1K1R3R b - -
For square g2, 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>".

g2: file=g; rank=2; fen_row_from_top=7; file_index=7


Prompt:
FEN: r5k1/pp4p1/1p1N3p/7q/4P3/2P2r2/PP4R1/6K1 w - - 4 33
Compressed rank 5 row: 7q
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: 4p1p1
File f changes from 1 to p. Rewrite the compressed row.

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


Prompt:
Board FEN before: k7/8/2K5/8/8/8/8/1R6
Apply square edits: b1 R->1; g1 1->R
Return the resulting board FEN only.

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


Prompt:
Starting FEN: r3kb1r/2B1pppp/p4n2/3p4/2nP2b1/2N1P3/PP3PPP/R3KBNR w KQkq -
Move: a2a4
List the square lookups and rank edits.

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

Lookup: a2=white pawn; a4=empty.
Squares: a2 white pawn->empty; a4 empty->white pawn.
Ranks: rank 2 a P->1; rank 4 a 1->P.


Prompt:
Starting FEN: r2rb1k1/pp3pp1/4p1p1/1P2B3/2PnR3/2Q3PP/P5P1/R5K1 b - - 0 1
Move: a8c8
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 a8c8.
Lookup: a8=black rook; c8=empty.
Squares: a8 black rook->empty; c8 empty->black rook.
Ranks: rank 8 a r->1; rank 8 c 1->r.
Result FEN: 2rrb1k1/pp3pp1/4p1p1/1P2B3/2PnR3/2Q3PP/P5P1/R5K1 w - - 1 2


Prompt:
Starting FEN: rnb1kbnr/ppp2ppp/8/3P4/7q/6p1/PPPP2KP/RNBQ1BNR b kq - 0 6
Move: h4e4
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: 6

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

Rows: rank 4 7q->4q3.
Result FEN: rnb1kbnr/ppp2ppp/8/3P4/4q3/6p1/PPPP2KP/RNBQ1BNR w kq - 1 7


Prompt:
Starting FEN: r2r2k1/p4ppp/2p1qnn1/2P1p3/1P2p3/P1N1P3/1B3PPP/R1Q2RK1 w - - 7 21
After the moves c1d2, what is the resulting position?
State needed for full FEN:
Side to move: white
Castling rights: none
En passant: none
Halfmove clock: 7
Fullmove number: 21

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

Result FEN: r2r2k1/p4ppp/2p1qnn1/2P1p3/1P2p3/P1N1P3/1B1Q1PPP/R4RK1 b - - 8 21


Prompt:
FEN: 5B2/8/p1p4p/3k2p1/5p2/1PK2P2/P5PP/8 b - - 2 34
List the material inventory by side and piece type.

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

White inventory: king=c3; queen=none; rook=none; bishop=f8; knight=none; pawn=a2,g2,h2,b3,f3.
Black inventory: king=d5; queen=none; rook=none; bishop=none; knight=none; pawn=f4,g5,a6,c6,h6.


Prompt:
FEN: 1rr3k1/1p4pp/2pbN3/p3p3/P2P4/4P3/5PPP/1RR3K1 b - - 1 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=0; rook=2; bishop=0; knight=1; pawn=6.
Black counts: king=1; queen=0; rook=2; bishop=1; knight=0; pawn=6.


Prompt:
FEN: 6k1/3n1pp1/4pn1p/3pN3/1b6/4P1B1/5PPP/4K3 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=4; total=10.
Black values: king=0; queen=0; rook=0; bishop=3; knight=6; pawn=5; total=14.


Prompt:
FEN: 6k1/3r2p1/2R4p/p6P/2p1p3/2P2r2/PP2KP1R/8 b - - 0 35
Trace inventory, counts, values, and material balance.

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

Inventory: white king=e2; queen=none; rook=h2,c6; bishop=none; knight=none; pawn=a2,b2,f2,c3,h5 | black king=g8; queen=none; rook=f3,d7; bishop=none; knight=none; pawn=c4,e4,a5,h6,g7
Counts: white king=1; queen=0; rook=2; bishop=0; knight=0; pawn=5 | black king=1; queen=0; rook=2; bishop=0; knight=0; pawn=5
Values: white total=15; black total=15
Balance: Material is equal.


Prompt:
Starting FEN: r2qkbnr/pp2pppp/3p2n1/2pP4/2P1PP2/5b1P/PP4P1/RNBQKB1R w KQkq - 0 8
After the moves d1f3 a8c8 e1e2, what is the resulting position?
State needed for full FEN:
Side to move: white
Castling rights: KQkq
En passant: none
Halfmove clock: 0
Fullmove number: 8

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

Result FEN: 2rqkbnr/pp2pppp/3p2n1/2pP4/2P1PP2/5Q1P/PP2K1P1/RNB2B1R b k - 2 9


Prompt:
Position (FEN): 1r1q1rk1/pp3ppp/3bp3/1Q1pN3/3PbP2/1P2P3/PB4PP/2R2RK1 b - -
Show me the board.


rn2kb1r/ppp2p2/4p2q/4Nbp1/Q1PPp3/P3P3/1P4PP/RNB2RK1 b kq - 2 12

Prompt:
Here is the current board:
8 r n . . k b . r
7 p p p . . p . .
6 . . . . p . . q
5 . . . . N b p .
4 Q . P P p . . .
3 P . . . P . . .
2 . P . . . . P P
1 R N B . . 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: kq
En passant: none
Halfmove clock: 2
Fullmove number: 12

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


Prompt:
FEN: r2qkb1r/1pp2ppp/n3pn2/3p3Q/3P4/4P3/1PP2PPP/RNB1K1NR w KQkq - 2 8
What piece is on c2?

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: 1R6/3qbppk/6n1/3pB1Pp/2pP2b1/p1P3N1/P1Q2PP1/6K1 b - -
What is the material count for both sides?

White (11 pieces): 1 bishop, 1 king, 1 knight, 6 pawns, 1 queen, 1 rook. Black (11 pieces): 2 bishops, 1 king, 1 knight, 6 pawns, 1 queen. White is up 2 point(s) of material.


Prompt:
FEN: 8/8/8/8/B7/2K1P3/4b3/2k5 b - -
What is on e2?

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


Prompt:
FEN: 4kbnr/1p1npp1p/3p2p1/qPp4Q/4P3/2NP4/1P1K1PPP/r1BR4 w k - 0 13
What is the compressed FEN row for rank 6?

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


Prompt:
FEN: 1rr5/2k5/3Q2P1/4P1P1/p2P4/Pp1K4/8/2q5 b - - 3 39
For square d6, 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>".

d6: file=d; rank=6; fen_row_from_top=3; file_index=4


Prompt:
FEN: rn2kbnr/pb2qppp/1pppp3/8/3PP3/2P1B1P1/PP2BP1P/RN1QK1NR b KQkq - 0 7
Compressed rank 3 row: 2P1B1P1
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: 2BpN3
File e changes from N to 1. Rewrite the compressed row.

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


1r1q1rk1/2p1ppbp/p2pbnp1/8/1n1P4/P1N1PNP1/1P2QPBP/R1BR2K1 b - -

Prompt:
Board FEN before: 1r1q1rk1/2p1ppbp/p2pbnp1/8/1n1P4/P1N1PNP1/1P2QPBP/R1BR2K1
Apply square edits: b4 n->1; c2 1->n
Return the resulting board FEN only.

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

Result board FEN: 1r1q1rk1/2p1ppbp/p2pbnp1/8/3P4/P1N1PNP1/1Pn1QPBP/R1BR2K1


Prompt:
Starting FEN: r1q2rk1/3nbppp/1pp1pn2/2Pp4/1P1P1B2/2NQPN2/5PPP/R4RK1 b - -
Move: e7d8
List the square lookups and rank edits.

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

Lookup: e7=black bishop; d8=empty.
Squares: e7 black bishop->empty; d8 empty->black bishop.
Ranks: rank 7 e b->1; rank 8 d 1->b.


Prompt:
Starting FEN: 8/3kP3/8/PN4B1/K3r3/8/8/8 w - - 0 1
Move: b5d4
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 b5d4.
Lookup: b5=white knight; d4=empty.
Squares: b5 white knight->empty; d4 empty->white knight.
Ranks: rank 5 b N->1; rank 4 d 1->N.
Result FEN: 8/3kP3/8/P5B1/K2Nr3/8/8/8 b - - 1 1


Prompt:
Starting FEN: 1R6/1p2rpk1/p1p3p1/3p4/1P6/P2K4/8/8 w - - 2 38
Move: d3c3
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: 38

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


Prompt:
Starting FEN: 5K2/1p4q1/p7/8/8/1k6/8/8 w - - 0 60
After the moves f8e8, 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: 60

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


Prompt:
FEN: 3r2k1/3q1pp1/1R3n1p/8/8/3B1QPP/P4P2/6K1 w - - 1 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=g1; queen=f3; rook=b6; bishop=d3; knight=none; pawn=a2,f2,g3,h3.
Black inventory: king=g8; queen=d7; rook=d8; bishop=none; knight=f6; pawn=h6,f7,g7.


Prompt:
FEN: r4rk1/pQpn2pp/5p2/8/3q4/3B4/P1PB2PP/R3R1K1 w - - 3 19
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=0; pawn=4.
Black counts: king=1; queen=1; rook=2; bishop=0; knight=1; pawn=5.


Prompt:
FEN: 1k6/3R4/2K5/2N5/8/8/2n5/8 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=5; bishop=0; knight=3; pawn=0; total=8.
Black values: king=0; queen=0; rook=0; bishop=0; knight=3; pawn=0; total=3.


Prompt:
FEN: 2br3r/p3k1p1/1p5p/P1n1Pp1B/8/4B2P/2P2PP1/RN4K1 b - - 0 23
Trace inventory, counts, values, and material balance.

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

Inventory: white king=g1; queen=none; rook=a1; bishop=e3,h5; knight=b1; pawn=c2,f2,g2,h3,a5,e5 | black king=e7; queen=none; rook=d8,h8; bishop=c8; knight=c5; pawn=f5,b6,h6,a7,g7
Counts: white king=1; queen=0; rook=1; bishop=2; knight=1; pawn=6 | black king=1; queen=0; rook=2; bishop=1; knight=1; pawn=5
Values: white total=20; black total=21
Balance: Black is up 1 point(s) of material.


Prompt:
Starting FEN: 4k3/pp2b3/3p2p1/2r1r1Np/4P2P/2P1NP2/PP4P1/R4RK1 w - - 3 26
After the moves e3d1 e5e6, what is the resulting position?
State needed for full FEN:
Side to move: white
Castling rights: none
En passant: none
Halfmove clock: 3
Fullmove number: 26

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


Prompt:
Position (FEN): r4k2/pp4p1/n2b4/8/3q4/4pB1P/PP2Q1P1/R5KR w - - 0 32
Show me the board.


Prompt:
Here is the current board:
8 . . . . . . r .
7 . . . . . . . p
6 p . . k . p . .
5 . . p . p . . .
4 P . . . b . . .
3 . . . r . . . B
2 . . . . . 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: white
Castling rights: none
En passant: none
Halfmove clock: 4
Fullmove number: 25

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


Prompt:
FEN: r1bqk1nr/1p2ppbp/p2p2p1/4n3/3NP3/2N1BP2/PPPQ2PP/R3KB1R w KQkq - 4 9
What piece is on e3?

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: rn1qkb1r/ppp2ppp/3p1n2/4P3/2Bp4/5b2/PPP2PPP/RNBQ1RK1 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 (16 pieces): 2 bishops, 1 king, 2 knights, 8 pawns, 1 queen, 2 rooks. Black is up 4 point(s) of material.


Prompt:
FEN: rn1qr1k1/5ppp/2p1p3/p1B5/1p1P4/P3PN2/1Q3PPP/2R2bK1 w - - 0 17
What is on c1?

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


Prompt:
FEN: 8/8/2k5/Q7/3K4/3N4/8/8 b - -
What is the compressed FEN row for rank 3?

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


Prompt:
FEN: rn1qkbnr/pbpp1ppp/1p2p3/8/2BPP3/2N5/PPP2PPP/R1BQK1NR b KQkq - 0 4
For square e1, 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>".

e1: file=e; rank=1; fen_row_from_top=8; file_index=5


Prompt:
FEN: r1bqkr2/pp6/3p1Bp1/n3p2p/1N1pP3/P2P2Q1/BPP3PP/R3K2R b KQq - 0 17
Compressed rank 5 row: n3p2p
Expand it into file cells a through h.

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


r3kb1r/1pp2ppp/p1n5/3qp3/8/1PNP1b2/PBP2PPP/R2Q1RK1 w kq - 0 11

Prompt:
Rank 2 row before: PBP2PPP
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: 2r1kb1r/1bqn1ppp/p3p3/1p2P1P1/2p2P1Q/2P1P3/P1BN3P/R1B2RK1
Apply square edits: h7 p->1; h6 1->p
Return the resulting board FEN only.

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

Result board FEN: 2r1kb1r/1bqn1pp1/p3p2p/1p2P1P1/2p2P1Q/2P1P3/P1BN3P/R1B2RK1


Prompt:
Starting FEN: br2r1k1/p4pp1/3q1n1p/4PQ1P/3B4/2PB1P2/P5P1/R4RK1 b - - 0 24
Move: e8e6
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 rook; e6=empty.
Squares: e8 black rook->empty; e6 empty->black rook.
Ranks: rank 8 e r->1; rank 6 e 1->r.


Prompt:
Starting FEN: 5rk1/5Qpp/8/8/8/1BR5/8/1K6 b - - 0 1
Move: g8h8
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 g8h8.
Lookup: g8=black king; h8=empty.
Squares: g8 black king->empty; h8 empty->black king.
Ranks: rank 8 g k->1; rank 8 h 1->k.
Result FEN: 5r1k/5Qpp/8/8/8/1BR5/8/1K6 w - - 1 2


Prompt:
Starting FEN: 8/8/2P5/8/R5p1/5k1p/P6P/4B2K w - - 0 49
Move: e1d2
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: 49

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


Prompt:
Starting FEN: rn1qkb1r/pp3ppp/4bn2/2pp4/3P4/2N3P1/PPP1NPBP/R1BQK2R b KQkq - 0 1
After the moves c5c4, 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: rn1qkb1r/pp3ppp/4bn2/3p4/2pP4/2N3P1/PPP1NPBP/R1BQK2R w KQkq - 0 2


Prompt:
FEN: 8/p5bk/2p3pp/3p4/8/PB3PRN/KPb2r2/8 b - - 1 32
List the material inventory by side and piece type.

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

White inventory: king=a2; queen=none; rook=g3; bishop=b3; knight=h3; pawn=b2,a3,f3.
Black inventory: king=h7; queen=none; rook=f2; bishop=c2,g7; knight=none; pawn=d5,c6,g6,h6,a7.


Prompt:
FEN: r2q1rk1/pp1nbppp/4pn2/2p1p3/5P2/3P1N2/PPP3PP/RNBQ1RK1 w - - 0 10
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=2; pawn=7.
Black counts: king=1; queen=1; rook=2; bishop=1; knight=2; pawn=8.


Prompt:
FEN: r2qk2r/1pp2p2/p1nb2pp/4p3/3pPPQ1/1N1P3P/PPP3P1/R1B2RK1 b kq - 0 13
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=8; total=33.
Black values: king=0; queen=9; rook=10; bishop=3; knight=3; pawn=8; total=33.


Prompt:
FEN: 8/p7/1pkp2K1/8/PP4RP/2r5/8/8 b - - 0 44
Trace inventory, counts, values, and material balance.

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

Inventory: white king=g6; queen=none; rook=g4; bishop=none; knight=none; pawn=a4,b4,h4 | black king=c6; queen=none; rook=c3; bishop=none; knight=none; pawn=b6,d6,a7
Counts: white king=1; queen=0; rook=1; bishop=0; knight=0; pawn=3 | black king=1; queen=0; rook=1; bishop=0; knight=0; pawn=3
Values: white total=8; black total=8
Balance: Material is equal.


Prompt:
Starting FEN: 8/8/8/5R2/5B2/7P/4kPPK/r1r5 b - - 10 51
After the moves c1f1 f4b8 f1h1, what is the resulting position?
State needed for full FEN:
Side to move: black
Castling rights: none
En passant: none
Halfmove clock: 10
Fullmove number: 51

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


Prompt:
Position (FEN): rnbqkbnr/p2p1ppp/1pp1p3/8/4P3/2NP4/PPP2PPP/R1BQKBNR w KQkq - 0 4
Show me the board.

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


Prompt:
Here is the current board:
8 r n b q . r k .
7 p p p . b p p p
6 . . . p . n . .
5 . . . . . . . .
4 . . . . . . . .
3 . . N P . N . .
2 P P P . B P P P
1 R . B 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: 0
Fullmove number: 1

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

rnbq1rk1/ppp1bppp/3p1n2/8/8/2NP1N2/PPP1BPPP/R1BQ1RK1 b - - 0 1


Prompt:
FEN: r1b1kb1Q/pp5p/2nq1pp1/2pp4/3P4/2P5/PP2BPPP/RN2K1NR b KQq - 1 10
What piece is on b1?

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: R1b5/2r5/2p2k2/2N2p2/1P1K4/6P1/5P2/8 w - -
What is the material count for both sides?

White (6 pieces): 1 king, 1 knight, 3 pawns, 1 rook. Black (5 pieces): 1 bishop, 1 king, 2 pawns, 1 rook. White is up 1 point(s) of material.


Prompt:
FEN: R3r3/3k4/8/8/Pp2R3/1P4P1/3r1P1P/6K1 w - - 3 43
What is on b4?

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


Prompt:
FEN: r4rk1/pb6/2p1pn1p/qp6/1b1P4/4PN2/PPQ2PPP/R4RK1 w - -
What is the compressed FEN row for rank 2?

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


Prompt:
FEN: 4k1nr/p1pnq2p/1b1p4/3Qp1N1/PP2P3/2P5/5PPP/RNB2RK1 b k - 0 17
For square a6, 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>".

a6: file=a; rank=6; fen_row_from_top=3; file_index=1


Prompt:
FEN: 3k3r/pp3R2/2p1R2b/6p1/2P5/1P1N2BP/P6K/8 b - - 0 33
Compressed rank 8 row: 3k3r
Expand it into file cells a through h.

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


r1bqkbnr/pp3ppp/2n5/1BPpp3/3P4/2N5/PP3PPP/R1BQK1NR b KQkq -

Prompt:
Rank 8 row before: r1bqkbnr
File f changes from b to 1. Rewrite the compressed row.

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


Prompt:
Board FEN before: 4rk2/3r1p1p/3b1p2/P1p1p3/1pPpB3/1P1N4/2P4P/R6K
Apply square edits: d3 N->1; e5 p->N
Return the resulting board FEN only.

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

Result board FEN: 4rk2/3r1p1p/3b1p2/P1p1N3/1pPpB3/1P6/2P4P/R6K


Prompt:
Starting FEN: rnbq1rk1/pp2ppbp/2pp1np1/8/2BPP3/2N1B3/PPP1NPPP/R2Q1RK1 b - - 1 7
Move: c8f5
List the square lookups and rank edits.

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

Lookup: c8=black bishop; f5=empty.
Squares: c8 black bishop->empty; f5 empty->black bishop.
Ranks: rank 8 c b->1; rank 5 f 1->b.


Prompt:
Starting FEN: r1bk4/pp1p1p1p/2n1p1p1/8/2P5/1PNBP3/P4PPP/R3K1NR b KQ - 3 15
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: KQ
En passant: none
Halfmove clock: 3
Fullmove number: 15

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: r1bk4/pp1p3p/2n1p1p1/5p2/2P5/1PNBP3/P4PPP/R3K1NR w KQ - 0 16


Prompt:
Starting FEN: 5rk1/pb2bp1n/1p2pP1Q/3q3P/8/5N2/P4P2/1B1K1N1R w - - 0 1
Move: h6d2
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 6 1p2pP1Q->1p2pP2; rank 2 P4P2->P2Q1P2.
Result FEN: 5rk1/pb2bp1n/1p2pP2/3q3P/8/5N2/P2Q1P2/1B1K1N1R b - - 1 1


Prompt:
Starting FEN: r1b2rk1/ppp3p1/5p1p/4p3/2N1P3/3P1RP1/PPP2KP1/R7 b - - 1 19
After the moves c8e6, 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: 19

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

Result FEN: r4rk1/ppp3p1/4bp1p/4p3/2N1P3/3P1RP1/PPP2KP1/R7 w - - 2 20


Prompt:
FEN: rnbq1rk1/ppp2ppp/1b6/3nP1B1/3P4/2N2N2/PP4PP/R2QKB1R b KQ -
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=f1,g5; knight=c3,f3; pawn=a2,b2,g2,h2,d4,e5.
Black inventory: king=g8; queen=d8; rook=a8,f8; bishop=b6,c8; knight=d5,b8; pawn=a7,b7,c7,f7,g7,h7.


Prompt:
FEN: 2r1kb1r/pp1n1p1p/4bpp1/q1pp4/3P4/1PP1P1PP/P3NPB1/RN1QK2R w KQk - 0 11
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=2; pawn=8.
Black counts: king=1; queen=1; rook=2; bishop=2; knight=1; pawn=8.


Prompt:
FEN: r1b4r/pp1p4/1k5p/1NbQp1q1/2BpP3/8/PPP2PPP/R3K2R w KQ - 5 15
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=6; knight=0; pawn=6; total=31.


Prompt:
FEN: r1bqk2r/ppp2ppp/2n2n2/4N3/1bpP1B2/4P3/PP1N1PPP/R2QKB1R 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=d1; rook=a1,h1; bishop=f1,f4; knight=d2,e5; pawn=a2,b2,f2,g2,h2,e3,d4 | black king=e8; queen=d8; rook=a8,h8; bishop=b4,c8; knight=c6,f6; pawn=c4,a7,b7,c7,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=7
Values: white total=38; black total=38
Balance: Material is equal.


Prompt:
Starting FEN: 8/p7/1kp5/2N5/2p4p/8/PPB4P/1K2R3 b - - 0 38
After the moves c4c3 c2b3, 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: 38

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


Prompt:
Position (FEN): r3kbnr/p1p2ppp/1p1p4/4n1B1/4P3/1Q5P/PPP2P2/RN2KB1R w KQkq - 0 10
Show me the board.


rnbq1rk1/ppp1p1bp/3p1np1/5p2/3P4/1P3NP1/P1P1PPBP/RNBQ1RK1 w - - 0 7

Prompt:
Here is the current board:
8 r n b q . r k .
7 p p p . p . b p
6 . . . p . n p .
5 . . . . . p . .
4 . . . P . . . .
3 . P . . . N P .
2 P . P . P P B P
1 R N B 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: none
En passant: none
Halfmove clock: 0
Fullmove number: 7

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


Prompt:
FEN: 5k2/8/8/p7/P4p2/8/1P1K4/8 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: 5k2/bR3ppp/p1p5/6r1/1P6/8/8/1K6 b - - 0 47
What is the material count for both sides?

White (3 pieces): 1 king, 1 pawn, 1 rook. Black (8 pieces): 1 bishop, 1 king, 5 pawns, 1 rook. Black is up 7 point(s) of material.


Prompt:
FEN: r2qk2r/ppp2pbp/2n1bnp1/4p3/Q1Pp4/P2B1N1P/1P3PP1/RNB2RK1 w kq - 0 11
What is on h8?

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


Prompt:
FEN: r4r2/pp4kp/5p2/3q1p2/3pp3/PP1P1B2/3Q1PPP/R3K2R w KQ - 0 22
What is the compressed FEN row for rank 8?

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


Prompt:
FEN: r3r1k1/ppp3p1/3p3p/3P1p2/1P6/P2PPK2/2P3PP/R6R w - - 0 18
For square a8, 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>".

a8: file=a; rank=8; fen_row_from_top=1; file_index=1


Prompt:
FEN: r1bq1rk1/p2pbpp1/2p2n1p/4p3/2B1P3/2N5/PPPB1PPP/R2QR1K1 b - - 1 10
Compressed rank 7 row: p2pbpp1
Expand it into file cells a through h.

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


Prompt:
Rank 3 row before: 2NP4
File c changes from N to 1. Rewrite the compressed row.

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


r3k2r/ppqn1pp1/2pbpnp1/6B1/3P4/2P2N2/PP2NPPP/R2QK2R w KQkq - 4 12

Prompt:
Board FEN before: r3k2r/ppqn1pp1/2pbpnp1/6B1/3P4/2P2N2/PP2NPPP/R2QK2R
Apply square edits: g5 B->1; c1 1->B
Return the resulting board FEN only.

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

Result board FEN: r3k2r/ppqn1pp1/2pbpnp1/8/3P4/2P2N2/PP2NPPP/R1BQK2R


Prompt:
Starting FEN: 6k1/4pp1p/1p1r2p1/6q1/1PPb4/5Q1P/P1R2PP1/3R2K1 b - -
Move: g5e5
List the square lookups and rank edits.

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

Lookup: g5=black queen; e5=empty.
Squares: g5 black queen->empty; e5 empty->black queen.
Ranks: rank 5 g q->1; rank 5 e 1->q.


Prompt:
Starting FEN: 6k1/5ppp/6n1/2r5/p7/2N5/1PP2PPP/R2r3K w - - 0 26
Move: c3d1
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: 26

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

Move 1: white knight c3d1. Captures black rook on d1.
Lookup: c3=white knight; d1=black rook.
Squares: c3 white knight->empty; d1 black rook->white knight.
Ranks: rank 3 c N->1; rank 1 d r->N.
Result FEN: 6k1/5ppp/6n1/2r5/p7/8/1PP2PPP/R2N3K b - - 0 26


Prompt:
Starting FEN: 2r3k1/6p1/P3pp2/3pN2p/R2n4/7P/5PP1/6K1 w - - 0 1
Move: a4a5
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 R2n4->3n4; rank 5 3pN2p->R2pN2p.
Result FEN: 2r3k1/6p1/P3pp2/R2pN2p/3n4/7P/5PP1/6K1 b - - 1 1


Prompt:
Starting FEN: 3r2k1/p3q1pp/8/3P4/3Q4/7P/PP4P1/5RK1 b - - 0 23
After the moves e7e8, 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: 23

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


Prompt:
FEN: 1rr1b3/1p1nBpk1/3p2p1/p2Pp2p/P1B1P2P/2NR2P1/RP3PK1/8 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=g2; queen=none; rook=a2,d3; bishop=c4,e7; knight=c3; pawn=b2,f2,g3,a4,e4,h4,d5.
Black inventory: king=g7; queen=none; rook=b8,c8; bishop=e8; knight=d7; pawn=a5,e5,h5,d6,g6,b7,f7.


Prompt:
FEN: 8/5k2/R6P/5P2/8/8/1r4K1/8 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=1; bishop=0; knight=0; pawn=2.
Black counts: king=1; queen=0; rook=1; bishop=0; knight=0; pawn=0.


Prompt:
FEN: 2kr1b1r/ppp2ppp/2n5/3q4/8/2P1B3/PP2NPPP/R2QK2R b 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=3; knight=3; pawn=6; total=31.
Black values: king=0; queen=9; rook=10; bishop=3; knight=3; pawn=6; total=31.


Prompt:
FEN: r2q3r/pbp2pk1/1p1p2p1/6b1/2P1PP1N/2NK2PQ/PP6/7R b - - 0 22
Trace inventory, counts, values, and material balance.

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

Inventory: white king=d3; queen=h3; rook=h1; bishop=none; knight=c3,h4; pawn=a2,b2,g3,c4,e4,f4 | black king=g7; queen=d8; rook=a8,h8; bishop=g5,b7; knight=none; pawn=b6,d6,g6,a7,c7,f7
Counts: white king=1; queen=1; rook=1; bishop=0; knight=2; pawn=6 | black king=1; queen=1; rook=2; bishop=2; knight=0; pawn=6
Values: white total=26; black total=31
Balance: Black is up 5 point(s) of material.


Prompt:
Starting FEN: rnb1kb1r/2p2ppp/p2qpn2/1p6/8/1BNP1N2/PPP1QPPP/R1B1K2R b KQkq - 1 8
After the moves f6d7 d3d4, what is the resulting position?
State needed for full FEN:
Side to move: black
Castling rights: KQkq
En passant: none
Halfmove clock: 1
Fullmove number: 8

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

Result FEN: rnb1kb1r/2pn1ppp/p2qp3/1p6/3P4/1BN2N2/PPP1QPPP/R1B1K2R b KQkq - 0 9


Prompt:
Position (FEN): 8/pR2bk2/1p4pp/1P2Bp2/r4P1P/6K1/8/8 w - - 22 49
Show me the board.


Prompt:
Here is the current board:
8 . r q . k . r .
7 . p . . b p . .
6 p . . p . . . .
5 . . p P p . B .
4 . . P . . . N .
3 P . . P . . . .
2 . P . . . . P .
1 . . . Q 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: 26

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


Prompt:
FEN: r1bqrnk1/pp2ppbp/2p2np1/3p4/2PP4/1P3NP1/PB1NPPBP/R2Q1RK1 w - - 3 10
What piece is on a2?

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: 5rk1/ppp2ppp/8/1P1r4/8/8/PP3PPK/2R1R3 w - - 0 22
What is the material count for both sides?

White (8 pieces): 1 king, 5 pawns, 2 rooks. Black (9 pieces): 1 king, 6 pawns, 2 rooks. Black is up 1 point(s) of material.


Prompt:
FEN: 8/ppkb3p/4p3/5p2/3R3P/P1P1P3/1P6/3KB1r1 b - - 1 29
What is on c7?

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


Prompt:
FEN: r1bqkb1r/ppp2ppp/2n2n2/3pp3/3P4/2P1P1P1/PP3PBP/RNBQK1NR b KQkq - 2 5
What is the compressed FEN row for rank 8?

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


Prompt:
FEN: r5kr/p2n1qBp/6p1/1p3b2/8/5Q2/PPP2PPP/4RRK1 b - - 0 22
For square c6, 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>".

c6: file=c; rank=6; fen_row_from_top=3; file_index=3


Prompt:
FEN: 3rkbnr/1p3ppp/p1n1P3/8/8/5P2/PP1N1PBP/R1BKR3 b k - 4 13
Compressed rank 5 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: q3nB2
File f changes from B to 1. Rewrite the compressed row.

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


rnbqkb1r/ppp2ppp/4p3/8/4n3/3P1N2/PPP2PPP/R1BQKB1R w KQkq - 0 6

Prompt:
Board FEN before: rnbqkb1r/ppp2ppp/4p3/8/4n3/3P1N2/PPP2PPP/R1BQKB1R
Apply square edits: d1 Q->1; e2 1->Q
Return the resulting board FEN only.

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

Result board FEN: rnbqkb1r/ppp2ppp/4p3/8/4n3/3P1N2/PPP1QPPP/R1B1KB1R


Prompt:
Starting FEN: 3r2k1/pb3ppp/1n6/1PK1p3/8/2P5/P6P/5R2 w - - 0 30
Move: f1e1
List the square lookups and rank edits.

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

Lookup: f1=white rook; e1=empty.
Squares: f1 white rook->empty; e1 empty->white rook.
Ranks: rank 1 f R->1; rank 1 e 1->R.


Prompt:
Starting FEN: 5r2/ppp3k1/3pB1p1/3Pp2p/3rP3/1KP4P/P1P5/R6R b - - 0 30
Move: g6g5
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: 30

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

Move 1: black pawn g6g5.
Lookup: g6=black pawn; g5=empty.
Squares: g6 black pawn->empty; g5 empty->black pawn.
Ranks: rank 6 g p->1; rank 5 g 1->p.
Result FEN: 5r2/ppp3k1/3pB3/3Pp1pp/3rP3/1KP4P/P1P5/R6R w - - 0 31


Prompt:
Starting FEN: 1n5k/4r1b1/1p1NB1pp/2p5/8/P1P2NP1/5P1P/2Bb2K1 w - - 0 1
Move: e6f5
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 6 1p1NB1pp->1p1N2pp; rank 5 2p5->2p2B2.
Result FEN: 1n5k/4r1b1/1p1N2pp/2p2B2/8/P1P2NP1/5P1P/2Bb2K1 b - - 1 1


Prompt:
Starting FEN: 8/1p6/8/1P3pk1/2P5/4PR1P/1r6/7K b - - 0 45
After the moves b2h2, 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: 45

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


Prompt:
FEN: 1k2r3/ppp3pp/1bn5/8/2P1N3/2P1p2P/P4rP1/R1B1K2R w - - 2 25
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=e4; pawn=a2,g2,c3,h3,c4.
Black inventory: king=b8; queen=none; rook=f2,e8; bishop=b6; knight=c6; pawn=e3,a7,b7,c7,g7,h7.


Prompt:
FEN: 1b6/4k3/5n2/8/4K3/8/8/8 w - - 16 48
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=0.
Black counts: king=1; queen=0; rook=0; bishop=1; knight=1; pawn=0.


Prompt:
FEN: 3r2k1/4Q2p/p4Rp1/1ppq4/P7/1P5P/6P1/7K 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=5; bishop=0; knight=0; pawn=4; total=18.
Black values: king=0; queen=9; rook=5; bishop=0; knight=0; pawn=5; total=19.


Prompt:
FEN: rb3rk1/2p2p1p/2Pp1qb1/p1n1pNp1/Q1N1P1B1/2P1B1P1/5P1K/R4R2 w - - 4 26
Trace inventory, counts, values, and material balance.

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

Inventory: white king=h2; queen=a4; rook=a1,f1; bishop=e3,g4; knight=c4,f5; pawn=f2,c3,g3,e4,c6 | black king=g8; queen=f6; rook=a8,f8; bishop=g6,b8; knight=c5; pawn=a5,e5,g5,d6,c7,f7,h7
Counts: white king=1; queen=1; rook=2; bishop=2; knight=2; pawn=5 | black king=1; queen=1; rook=2; bishop=2; knight=1; pawn=7
Values: white total=36; black total=35
Balance: White is up 1 point(s) of material.


Prompt:
Starting FEN: rn3bnr/p2k2pp/1p1p2p1/6B1/3N4/8/PPN2PPP/R2QR1K1 w - - 0 14
After the moves e1e2 g8h6, 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: 14

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

Result FEN: rn3b1r/p2k2pp/1p1p2pn/6B1/3N4/8/PPN1RPPP/R2Q2K1 w - - 2 15


Prompt:
Position (FEN): rn2kb1r/pbpp4/1p2pq2/7p/3PN3/3B1N2/PPP2PPP/R2Q1RK1 b kq - 1 11
Show me the board.


Prompt:
Here is the current board:
8 . . . . . . . .
7 . . . . k p . .
6 . . . . . . . P
5 . . . . K P . .
4 . . . . . . . .
3 . p . . . . . .
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: 51

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


Prompt:
FEN: 5k2/2p4p/6p1/R7/3P1P2/1P4P1/P6P/2K1r3 w - - 1 42
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: r2qN2k/pppb2p1/2np3p/8/2Q5/8/PP1N1PPP/R3R1K1 w - -
What is the material count for both sides?

White (11 pieces): 1 king, 2 knights, 5 pawns, 1 queen, 2 rooks. Black (11 pieces): 1 bishop, 1 king, 1 knight, 6 pawns, 1 queen, 1 rook. White is up 4 point(s) of material.


Prompt:
FEN: 6k1/1p4pp/8/p1R5/6P1/7P/PP4K1/3r4 b - -
What is on b2?

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


Prompt:
FEN: 3q1b2/pkp1n3/1p5p/7p/4Q3/8/PB3PPP/4R1K1 b - - 1 24
What is the compressed FEN row for rank 5?

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


Prompt:
FEN: r3kbqr/pppn3p/3pp3/4PnB1/3PN1QP/3B4/PPP3P1/R3KR2 w Qkq -
For square h1, 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>".

h1: file=h; rank=1; fen_row_from_top=8; file_index=8


Prompt:
FEN: 5rk1/rp3ppp/2p5/p2n4/8/2P2PN1/PP3P1P/R3R1K1 w - -
Compressed rank 1 row: R3R1K1
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: 3R3P
File g changes from 1 to r. Rewrite the compressed row.

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


Prompt:
Board FEN before: rn3rk1/pbp2p1p/1p1qpBp1/4N3/2PP4/P2Q4/1P3PPP/R4RK1
Apply square edits: a3 P->1; a4 1->P
Return the resulting board FEN only.

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

Result board FEN: rn3rk1/pbp2p1p/1p1qpBp1/4N3/P1PP4/3Q4/1P3PPP/R4RK1


Prompt:
Starting FEN: rnbqk2r/pppp1ppp/6n1/2b5/2P1PP2/2N2N2/PP4PP/R1BQKB1R b KQkq -
Move: a7a5
List the square lookups and rank edits.

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

Lookup: a7=black pawn; a5=empty.
Squares: a7 black pawn->empty; a5 empty->black pawn.
Ranks: rank 7 a p->1; rank 5 a 1->p.


Prompt:
Starting FEN: 3r4/p3R1kp/6p1/1p1p1r2/5q2/2PQ3P/PPB2P2/5K2 b - - 5 27
Move: g7f8
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: 5
Fullmove number: 27

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

Move 1: black king g7f8.
Lookup: g7=black king; f8=empty.
Squares: g7 black king->empty; f8 empty->black king.
Ranks: rank 7 g k->1; rank 8 f 1->k.
Result FEN: 3r1k2/p3R2p/6p1/1p1p1r2/5q2/2PQ3P/PPB2P2/5K2 w - - 6 28


Prompt:
Starting FEN: 4r1k1/pp1n1ppp/2pQ4/8/8/2N4P/PP3PP1/6K1 b - - 0 22
Move: d7b8
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: 22

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

Rows: rank 7 pp1n1ppp->pp3ppp; rank 8 4r1k1->1n2r1k1.
Result FEN: 1n2r1k1/pp3ppp/2pQ4/8/8/2N4P/PP3PP1/6K1 w - - 1 23


Prompt:
Starting FEN: R7/5ppk/4p3/p1r1P2p/1p3P2/1P4PP/6K1/8 w - - 0 1
After the moves g2g1, 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>".


Prompt:
FEN: r1bqnrk1/p1ppbppp/2p5/4P3/8/P1N1B3/1PP2PPP/R2QKB1R b KQ -
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=f1,e3; knight=c3; pawn=b2,c2,f2,g2,h2,a3,e5.
Black inventory: king=g8; queen=d8; rook=a8,f8; bishop=e7,c8; knight=e8; pawn=c6,a7,c7,d7,f7,g7,h7.


Prompt:
FEN: 6k1/5p2/2r1p1p1/3p1n2/p2P3p/1P5P/P2qNPP1/3R2K1 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=1; bishop=0; knight=1; pawn=6.
Black counts: king=1; queen=1; rook=1; bishop=0; knight=1; pawn=6.


Prompt:
FEN: 2r1k2r/1p1nqpp1/p2p2bp/1P2p3/4P1P1/3PBN1P/1P3PK1/R2Q1R2 b k - 0 18
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: rn1qkbnr/pppb2pp/4p3/3p1p2/3P1PP1/2N4P/PPPQP3/R1B1KBNR 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=d2; rook=a1,h1; bishop=c1,f1; knight=g1,c3; pawn=a2,b2,c2,e2,h3,d4,f4,g4 | black king=e8; queen=d8; rook=a8,h8; bishop=d7,f8; knight=b8,g8; pawn=d5,f5,e6,a7,b7,c7,g7,h7
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: rn1qkb1r/2pb1pp1/1p1p1n1p/pP2p3/P1B1P3/2PP1N1P/5PP1/RNBQK2R w KQkq - 1 10
After the moves c1e3 a8a7 b1d2, 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: 10

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

Result FEN: 1n1qkb1r/r1pb1pp1/1p1p1n1p/pP2p3/P1B1P3/2PPBN1P/3N1PP1/R2QK2R b KQk - 4 11


Prompt:
Position (FEN): 8/8/8/2R5/1K1k4/8/8/8 b - -
Show me the board.


Prompt:
Here is the current board:
8 . . . . . . . .
7 . p . . . . p .
6 . k p . . b . .
5 p . . . . . . .
4 . . . . . . . P
3 . . . . . . r 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: white
Castling rights: none
En passant: none
Halfmove clock: 0
Fullmove number: 43

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


Prompt:
FEN: 2r2rk1/1p2qpp1/p3p2p/1b1n4/P3N3/1P2PN2/3Q1PPP/R1R3K1 b - - 0 19
What piece is on b7?

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: 5k2/8/4KP2/8/p7/P7/1P6/8 b - -
What is the material count for both sides?

White (4 pieces): 1 king, 3 pawns. Black (2 pieces): 1 king, 1 pawn. White is up 2 point(s) of material.


Prompt:
FEN: r5r1/p1p1k2p/1p1pP3/4n1q1/1P4n1/P1P5/1B1NQPb1/R3R1K1 w - - 0 25
What is on g1?

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


Prompt:
FEN: r3k2r/3bqppp/4pn2/3p4/pn1P4/1BQ2N2/2P1NPPP/2KR3R w kq - 0 19
What is the compressed FEN row for rank 1?

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


Prompt:
FEN: r1bk3r/2p2pb1/2n2p1p/p3p3/1pPP4/1P3N2/2N2PPP/R1B2RK1 b - - 0 17
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: r6r/3b1pk1/1p1p2p1/2n1p2P/p1P1PqP1/P1N5/1P2B1Q1/1K1R3R b - -
Compressed rank 5 row: 2n1p2P
Expand it into file cells a through h.

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


r1b1kbnr/p2p1ppp/pq1P4/8/8/p1P2N2/5PPP/RNBQK2R w KQkq -

Prompt:
Rank 3 row before: p1P2N2
File f changes from N to 1. Rewrite the compressed row.

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


Prompt:
Board FEN before: 8/8/4K3/2R5/n7/8/8/4k3
Apply square edits: e6 K->1; d5 1->K
Return the resulting board FEN only.

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


Prompt:
Starting FEN: r1bqkb1r/ppp2ppp/2n1p3/3pP3/3Pn3/2PB4/PP1N1PPP/R1BQK1NR b KQkq - 1 6
Move: g7g5
List the square lookups and rank edits.

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

Lookup: g7=black pawn; g5=empty.
Squares: g7 black pawn->empty; g5 empty->black pawn.
Ranks: rank 7 g p->1; rank 5 g 1->p.


Prompt:
Starting FEN: r3r1k1/ppp2ppp/2nq4/2b5/4p3/2BP2PP/PP2PPB1/R2Q1RK1 b - - 0 1
Move: c5a3
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 bishop c5a3.
Lookup: c5=black bishop; a3=empty.
Squares: c5 black bishop->empty; a3 empty->black bishop.
Ranks: rank 5 c b->1; rank 3 a 1->b.
Result FEN: r3r1k1/ppp2ppp/2nq4/8/4p3/b1BP2PP/PP2PPB1/R2Q1RK1 w - - 1 2


Prompt:
Starting FEN: 8/8/8/6p1/4K1P1/6k1/8/8 w - - 0 1
Move: e4f5
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: r4rk1/p3b2p/2p1p2p/3qN3/3P4/2P3Q1/P4PPP/R4RK1 b - - 2 21
After the moves g8h8, 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: 21

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

Result FEN: r4r1k/p3b2p/2p1p2p/3qN3/3P4/2P3Q1/P4PPP/R4RK1 w - - 3 22


Prompt:
FEN: r5k1/ppPr2pp/2nB1pn1/5P2/1N6/1KP3P1/PP1Rb2P/8 b - - 0 22
List the material inventory by side and piece type.

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

White inventory: king=b3; queen=none; rook=d2; bishop=d6; knight=b4; pawn=a2,b2,h2,c3,g3,f5,c7.
Black inventory: king=g8; queen=none; rook=d7,a8; bishop=e2; knight=c6,g6; pawn=f6,a7,b7,g7,h7.


Prompt:
FEN: 2r1kr2/ppQ5/3p1pp1/4n3/4PP2/1P6/1PP3P1/1K1R1B1R 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=1; knight=0; pawn=6.
Black counts: king=1; queen=0; rook=2; bishop=0; knight=1; pawn=5.


Prompt:
FEN: r2qkb1r/pb1nnppp/1pp1p3/3pP3/3P4/2PBBN2/PPQ2PPP/RN2K2R b KQkq - 3 8
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: 8/8/4B1k1/8/5K2/3N4/8/8 w - -
Trace inventory, counts, values, and material balance.

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

Inventory: white king=f4; queen=none; rook=none; bishop=e6; knight=d3; pawn=none | black king=g6; queen=none; rook=none; bishop=none; knight=none; pawn=none
Counts: white king=1; queen=0; rook=0; bishop=1; knight=1; 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: r3r1k1/3q1pp1/p3b2p/np1p4/2pP4/P1P3NP/BP1Q1PP1/3RR1K1 w - - 0 22
After the moves a3a4 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: 22

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

Result FEN: r3r1k1/3q2p1/p3bp1p/np1p4/P1pP4/2P3NP/BP1Q1PP1/3RR1K1 w - - 0 23


Prompt:
Position (FEN): 4r2r/p1pk4/1p2pp2/6p1/3PRp2/2PR3P/PP3PP1/6K1 w - - 0 29
Show me the board.


Prompt:
Here is the current board:
8 r . . . k . . .
7 . . . p . . . .
6 b . . . . . p .
5 . . b . B . . .
4 . p P . P . . .
3 . B . P . . . .
2 . P . . . P P P
1 R N . . . 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: q
En passant: none
Halfmove clock: 0
Fullmove number: 22

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


Prompt:
FEN: 2k3rr/pp1b4/1qnb2n1/2ppp1Pp/7N/N1PP3P/PP1BQ1B1/R4R1K w - - 6 23
What piece is on a3?

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: rnbqk1nr/ppppbppp/8/4p3/3PP3/8/PPPB1PPP/RN1QKBNR w KQkq - 3 4
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: 2kr1b1r/pbppnppp/1pn1p3/8/2P5/1P1P4/P2QPPPP/RN2KBNR w KQ - 0 8
What is on a7?

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


Prompt:
FEN: r4r1k/1pq3p1/1p1N1p1p/3R4/b7/6QP/PP3PP1/4R1K1 w - -
What is the compressed FEN row for rank 7?

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


Prompt:
FEN: 4r1k1/5ppp/2p1r1n1/4P1P1/1P3P2/4Q3/8/5R1K b - -
For square f5, 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>".

f5: file=f; rank=5; fen_row_from_top=4; file_index=6


Prompt:
FEN: 8/7k/5p1p/5P1K/8/8/8/8 w - - 3 63
Compressed rank 2 row: 8
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: PPN2PP1
File d changes from 1 to R. Rewrite the compressed row.

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


Prompt:
Board FEN before: r3k1nr/p5pp/2p2p2/3pP3/3P2bN/2P3P1/P7/R1B1K2R
Apply square edits: g4 b->1; h5 1->b
Return the resulting board FEN only.

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

Result board FEN: r3k1nr/p5pp/2p2p2/3pP2b/3P3N/2P3P1/P7/R1B1K2R


Prompt:
Starting FEN: 1k6/pp1b1n1p/4p1p1/1P1p1pP1/P4P2/4r2P/4N3/3RK2R b K - 3 28
Move: d7c8
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=black bishop; c8=empty.
Squares: d7 black bishop->empty; c8 empty->black bishop.
Ranks: rank 7 d b->1; rank 8 c 1->b.


Prompt:
Starting FEN: 2Q5/1Q3p2/4p3/P3P3/5k2/3P4/8/4K3 b - - 0 46
Move: f4e3
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: 46

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

Move 1: black king f4e3.
Lookup: f4=black king; e3=empty.
Squares: f4 black king->empty; e3 empty->black king.
Ranks: rank 4 f k->1; rank 3 e 1->k.
Result FEN: 2Q5/1Q3p2/4p3/P3P3/8/3Pk3/8/4K3 w - - 1 47


Prompt:
Starting FEN: 3r2k1/7p/3q1p2/2p3p1/2Pb1p2/P4N1P/3Q1PP1/3R3K w - - 0 33
Move: f3e1
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: 33

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

Rows: rank 3 P4N1P->P6P; rank 1 3R3K->3RN2K.
Result FEN: 3r2k1/7p/3q1p2/2p3p1/2Pb1p2/P6P/3Q1PP1/3RN2K b - - 1 33


Prompt:
Starting FEN: 3rr1k1/p1b1n1p1/1p3p1p/2pb4/4p1PN/1P5P/PBP1BP2/2KR3R b - - 1 23
After the moves d5f7, 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: 23

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

Result FEN: 3rr1k1/p1b1nbp1/1p3p1p/2p5/4p1PN/1P5P/PBP1BP2/2KR3R w - - 2 24


Prompt:
FEN: rn3rk1/pb1pqppp/1p2pn2/2p5/NbPP4/3BPN2/PP3PPP/R1BQ1RK1 w - - 4 9
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=f3,a4; pawn=a2,b2,f2,g2,h2,e3,c4,d4.
Black inventory: king=g8; queen=e7; rook=a8,f8; bishop=b4,b7; knight=f6,b8; pawn=c5,b6,e6,a7,d7,f7,g7,h7.


Prompt:
FEN: 8/8/2k4p/2P1ppp1/1K5P/5P2/6P1/8 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=0; bishop=0; knight=0; pawn=4.
Black counts: king=1; queen=0; rook=0; bishop=0; knight=0; pawn=4.


Prompt:
FEN: 2b1kb1r/r2qn1p1/3p4/1N2pP1p/P2p2P1/1P3N2/5P1P/R1BQ1RK1 b k -
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=6; pawn=6; total=34.
Black values: king=0; queen=9; rook=10; bishop=6; knight=3; pawn=5; total=33.


Prompt:
FEN: 8/1N1n4/p7/P2k4/1P1Pp3/4b3/1B4K1/8 b - - 5 46
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=none; bishop=b2; knight=b7; pawn=b4,d4,a5 | black king=d5; queen=none; rook=none; bishop=e3; knight=d7; pawn=e4,a6
Counts: white king=1; queen=0; rook=0; bishop=1; knight=1; pawn=3 | black king=1; queen=0; rook=0; bishop=1; knight=1; pawn=2
Values: white total=9; black total=8
Balance: White is up 1 point(s) of material.


Prompt:
Starting FEN: 4rrk1/n1p3pp/pp2q3/2b5/P1Pp1B2/1P1B1n2/1KQ3PN/R7 w - - 0 27
After the moves a1g1 e6h6 b2a2, 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: 27

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

Result FEN: 4rrk1/n1p3pp/pp5q/2b5/P1Pp1B2/1P1B1n2/K1Q3PN/6R1 b - - 3 28


Prompt:
Position (FEN): 8/4kpp1/7p/8/7P/1P1RK1P1/1r3P2/8 b - -
Show me the board.


Prompt:
Here is the current board:
8 . . . . . . . .
7 . . . . . . . .
6 . p . . . k . p
5 b P . . . . . .
4 P . . . K . P .
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: black
Castling rights: none
En passant: none
Halfmove clock: 14
Fullmove number: 59

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


Prompt:
FEN: 8/8/8/4K3/3Q4/3k4/8/8 b - -
What piece is on e5?

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: 6k1/5ppp/4p3/8/4P3/2K2PP1/6bP/8 w - - 1 39
What is the material count for both sides?

White (5 pieces): 1 king, 4 pawns. Black (6 pieces): 1 bishop, 1 king, 4 pawns. Black is up 3 point(s) of material.


Prompt:
FEN: 1r3rk1/3q2p1/p1n2p2/1ppppP2/8/P2PBP2/1PP3PP/R3R1K1 b - - 0 25
What is on g1?

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


Prompt:
FEN: r2q1rk1/n1p1bpp1/p2p1n1p/1p2p3/PP2P1bP/1BPP1NP1/5P2/R1BQKN1R b KQ - 1 12
What is the compressed FEN row for rank 6?

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


Prompt:
FEN: 2k3nr/ppprqp2/1b5p/n2pP1p1/Q2P1B2/2P2N2/PP1N2PP/R4R1K w - - 0 16
For square a2, 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>".

a2: file=a; rank=2; fen_row_from_top=7; file_index=1


Prompt:
FEN: r4rk1/4qpp1/2pp3p/1p2p3/p3P3/P2P1PQP/bPP1K1P1/R6R w - - 0 19
Compressed rank 7 row: 4qpp1
Expand it into file cells a through h.

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


Prompt:
Rank 3 row before: 2Kn4
File b changes from 1 to K. Rewrite the compressed row.

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


Prompt:
Board FEN before: r3r1k1/5pp1/p1pqbn1p/3p4/P2P4/2P2P2/N1B3PP/1R1Q1RK1
Apply square edits: d6 q->1; c7 1->q
Return the resulting board FEN only.

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

Result board FEN: r3r1k1/2q2pp1/p1p1bn1p/3p4/P2P4/2P2P2/N1B3PP/1R1Q1RK1


Prompt:
Starting FEN: 8/4P1p1/2k2p1p/1p3P2/1K4PP/8/8/8 b - -
Move: c6d7
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 king; d7=empty.
Squares: c6 black king->empty; d7 empty->black king.
Ranks: rank 6 c k->1; rank 7 d 1->k.


Prompt:
Starting FEN: 6k1/5r1p/p5p1/3P1p2/4pqPQ/P1p4R/3RK2P/2r5 w - - 0 33
Move: h4g5
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: 33

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

Move 1: white queen h4g5.
Lookup: h4=white queen; g5=empty.
Squares: h4 white queen->empty; g5 empty->white queen.
Ranks: rank 4 h Q->1; rank 5 g 1->Q.
Result FEN: 6k1/5r1p/p5p1/3P1pQ1/4pqP1/P1p4R/3RK2P/2r5 b - - 1 33


Prompt:
Starting FEN: 8/p4p2/7p/2k1PB2/P1pp3P/1r4P1/3K4/8 b - - 0 42
Move: b3b1
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: 42

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


Prompt:
Starting FEN: r3kbnr/2q2ppp/p1b5/3pp3/6Q1/4P3/1PPP1PPP/R1B1K1NR b KQkq - 1 14
After the moves a6a5, what is the resulting position?
State needed for full FEN:
Side to move: black
Castling rights: KQkq
En passant: none
Halfmove clock: 1
Fullmove number: 14

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

Result FEN: r3kbnr/2q2ppp/2b5/p2pp3/6Q1/4P3/1PPP1PPP/R1B1K1NR w KQkq - 0 15


Prompt:
FEN: 4r3/2p3b1/p3k3/1p2Pr2/3P1Bp1/1PP3P1/P4R2/5RK1 b - - 0 28
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=none; rook=f1,f2; bishop=f4; knight=none; pawn=a2,b3,c3,g3,d4,e5.
Black inventory: king=e6; queen=none; rook=f5,e8; bishop=g7; knight=none; pawn=g4,b5,a6,c7.


Prompt:
FEN: r2qkb1r/pppn1ppp/3pbp2/8/2PP4/4P3/PP3PPP/RN1QKBNR 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=1; knight=2; pawn=8.
Black counts: king=1; queen=1; rook=2; bishop=2; knight=1; pawn=8.


Prompt:
FEN: 2k1r3/p3n1pp/1R3pb1/N1p5/2P1P1P1/4K2P/P1P5/7R b - - 0 30
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=6; total=19.
Black values: king=0; queen=0; rook=5; bishop=3; knight=3; pawn=5; total=16.


Prompt:
FEN: 8/8/4R3/3r1K2/3k4/8/8/8 w - - 10 96
Trace inventory, counts, values, and material balance.

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

Inventory: white king=f5; queen=none; rook=e6; bishop=none; knight=none; pawn=none | black king=d4; queen=none; rook=d5; bishop=none; knight=none; pawn=none
Counts: white king=1; queen=0; rook=1; bishop=0; knight=0; pawn=0 | black king=1; queen=0; rook=1; bishop=0; knight=0; pawn=0
Values: white total=5; black total=5
Balance: Material is equal.


Prompt:
Starting FEN: 2r2rk1/1bq1bpp1/3p3p/p1pPn3/PpB1P1n1/1P2BN2/4QPPP/2NR1RK1 w - - 9 22
After the moves f3g5 c7c6 e2b2, what is the resulting position?
State needed for full FEN:
Side to move: white
Castling rights: none
En passant: none
Halfmove clock: 9
Fullmove number: 22

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

Result FEN: 2r2rk1/1b2bpp1/2qp3p/p1pPn1N1/PpB1P1n1/1P2B3/1Q3PPP/2NR1RK1 b - - 12 23


Prompt:
Position (FEN): rnbqkb1r/pp2pppp/8/3p4/3pnB2/3BP3/PPP2PPP/RN1QK1NR w KQkq -
Show me the board.