r1bqkb1r/ppp2ppp/2n1P3/1N1pn3/5B2/8/PPP1PPPP/R2QKBNR w KQkq - 1 7

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

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


Prompt:
FEN: r4rk1/pp2bppp/1q3n2/2p1p3/4P1b1/2PB4/PPQNNPPP/R4RK1 w - - 2 13
What piece is on b6?

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/pp2pp2/2bp2p1/2nNb3/2P3BQ/4B3/PP4PP/3R1RK1 b - -
What is the material count for both sides?

White (12 pieces): 2 bishops, 1 king, 1 knight, 5 pawns, 1 queen, 2 rooks. Black (13 pieces): 2 bishops, 1 king, 1 knight, 6 pawns, 1 queen, 2 rooks. Black is up 1 point(s) of material.


Prompt:
FEN: r3kb1r/ppp1pp2/2nq1np1/5bNp/2B5/2NPQ2P/PPP2PP1/R1B1K2R b KQkq - 1 10
What is on c3?

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


Prompt:
FEN: 8/4k3/2Bp4/4b3/5qp1/8/6P1/3R2K1 w - - 2 55
What is the compressed FEN row for rank 8?

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


Prompt:
FEN: r3k2r/p5p1/1qppbn1p/4p3/4P3/3P3N/PPP2PPP/R1R4K w - - 0 18
For square d7, give the FEN row-from-top and file index.

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

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


Prompt:
FEN: r1b1k2r/ppppqppp/2n2n2/6B1/1bPNP3/2N2P2/PP4PP/R2QKB1R b KQkq - 0 8
Compressed rank 2 row: PP4PP
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: 5k2
File f changes from k to 1. Rewrite the compressed row.

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


rn3rk1/p4ppp/1ppq1n2/3p4/3P4/3QPN2/PP2NPPP/2R2RK1 b - -

Prompt:
Board FEN before: rn3rk1/p4ppp/1ppq1n2/3p4/3P4/3QPN2/PP2NPPP/2R2RK1
Apply square edits: d6 q->1; h2 P->q
Return the resulting board FEN only.

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

Result board FEN: rn3rk1/p4ppp/1pp2n2/3p4/3P4/3QPN2/PP2NPPq/2R2RK1


Prompt:
Starting FEN: rn3r2/5p1k/p4qpp/3p1n2/Np4Q1/1P3N1P/P1PP1PP1/R4RK1 w - - 2 20
Move: g4g3
List the square lookups and rank edits.

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

Lookup: g4=white queen; g3=empty.
Squares: g4 white queen->empty; g3 empty->white queen.
Ranks: rank 4 g Q->1; rank 3 g 1->Q.


Prompt:
Starting FEN: 2krr3/b3np2/p4q2/1pp2P1p/5Qp1/P1PB2B1/1P4PP/1K1R1R2 b - - 1 24
Move: f6h6
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: 24

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

Move 1: black queen f6h6.
Lookup: f6=black queen; h6=empty.
Squares: f6 black queen->empty; h6 empty->black queen.
Ranks: rank 6 f q->1; rank 6 h 1->q.
Result FEN: 2krr3/b3np2/p6q/1pp2P1p/5Qp1/P1PB2B1/1P4PP/1K1R1R2 w - - 2 25


Prompt:
Starting FEN: r2q1rk1/ppp1b1p1/3p1pP1/2n1p2p/3nP2P/1PN5/PBPP1PQ1/2KR1B1R w - - 0 14
Move: f1a6
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: 14

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

Rows: rank 1 2KR1B1R->2KR3R; rank 6 3p1pP1->B2p1pP1.
Result FEN: r2q1rk1/ppp1b1p1/B2p1pP1/2n1p2p/3nP2P/1PN5/PBPP1PQ1/2KR3R b - - 1 14


Prompt:
Starting FEN: rnbqk2r/pp3ppp/2p2n2/3P2B1/1b1Pp3/2N3P1/PP2PPBP/R2QK1NR b KQkq - 0 1
After the moves b7b6, 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: rnbqk2r/p4ppp/1pp2n2/3P2B1/1b1Pp3/2N3P1/PP2PPBP/R2QK1NR w KQkq - 0 2


Prompt:
FEN: 2r5/p2R4/7p/8/3P1b2/5kP1/PP3P2/5K2 w - -
List the material inventory by side and piece type.

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

White inventory: king=f1; queen=none; rook=d7; bishop=none; knight=none; pawn=a2,b2,f2,g3,d4.
Black inventory: king=f3; queen=none; rook=c8; bishop=f4; knight=none; pawn=h6,a7.


Prompt:
FEN: rnbqkb1r/3p1ppp/8/1p1p4/2p1nP2/5N2/PPP3PP/RNBQK2R b KQkq - 1 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=6.
Black counts: king=1; queen=1; rook=2; bishop=2; knight=2; pawn=7.


Prompt:
FEN: r3nrk1/2qpbppp/b7/p3pP2/1pPpP1P1/1P1P2NP/P3Q1B1/RN3RK1 w - - 1 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=6; pawn=8; total=36.
Black values: king=0; queen=9; rook=10; bishop=6; knight=3; pawn=8; total=36.


Prompt:
FEN: 7r/1b1N2k1/2n1p3/1p6/p1pP1P2/P1P5/2K3P1/8 b - - 0 34
Trace inventory, counts, values, and material balance.

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

Inventory: white king=c2; queen=none; rook=none; bishop=none; knight=d7; pawn=g2,a3,c3,d4,f4 | black king=g7; queen=none; rook=h8; bishop=b7; knight=c6; pawn=a4,c4,b5,e6
Counts: white king=1; queen=0; rook=0; bishop=0; knight=1; pawn=5 | black king=1; queen=0; rook=1; bishop=1; knight=1; pawn=4
Values: white total=8; black total=15
Balance: Black is up 7 point(s) of material.


Prompt:
Starting FEN: 7r/2k5/8/7R/6KP/5P2/8/8 b - - 4 58
After the moves h8e8 h5c5 c7d8, what is the resulting position?
State needed for full FEN:
Side to move: black
Castling rights: none
En passant: none
Halfmove clock: 4
Fullmove number: 58

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


Prompt:
Position (FEN): r1b1k2r/ppq2ppp/2nbpn2/2pp4/8/1P2PP2/PBPPN1PP/RN1QKB1R w KQkq - 3 8
Show me the board.

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


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

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

r3kb1r/p1qppppp/bp3n2/8/1n1PP3/5N2/PP2NPPP/RBBQ1RK1 b kq - 0 1


Prompt:
FEN: r2q1rk1/3b3p/p1p1p1p1/3pP2n/8/2PBP2P/PP4P1/R2Q1RK1 b - - 0 20
What piece is on a6?

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: r3k1nN/p2n1pp1/2p1b2p/1p1p4/3P3P/1R1B4/P1PK1PP1/4R3 b q -
What is the material count for both sides?

White (11 pieces): 1 bishop, 1 king, 1 knight, 6 pawns, 2 rooks. Black (12 pieces): 1 bishop, 1 king, 2 knights, 7 pawns, 1 rook. White is up 1 point(s) of material.


Prompt:
FEN: 4r3/p5pp/1p1k1p2/3P1K2/8/P6P/BP6/8 b - - 0 33
What is on d7?

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


Prompt:
FEN: 3rk3/p4p2/1p1b1nr1/q1p1P2p/5Q2/P1B1N3/1PB2PPP/1R2K2R b K - 0 25
What is the compressed FEN row for rank 3?

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


Prompt:
FEN: 8/8/R7/8/1R6/2k1K3/8/8 w - -
For square b4, 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>".

b4: file=b; rank=4; fen_row_from_top=5; file_index=2


Prompt:
FEN: 4qknr/Q1p2pbp/4p1p1/3pP3/3p4/P4N2/1PP2PPP/RNB3K1 w - - 0 15
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>".


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

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


rn1qkb1r/ppp1pppp/4bn2/8/2p5/N4NP1/PPQPPPBP/R1B1K2R b KQkq -

Prompt:
Board FEN before: rn1qkb1r/ppp1pppp/4bn2/8/2p5/N4NP1/PPQPPPBP/R1B1K2R
Apply square edits: h7 p->1; h5 1->p
Return the resulting board FEN only.

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

Result board FEN: rn1qkb1r/ppp1ppp1/4bn2/7p/2p5/N4NP1/PPQPPPBP/R1B1K2R


Prompt:
Starting FEN: 8/5p2/8/1PK3pp/P1P5/5p2/2P3kP/8 b - - 0 42
Move: g2h1
List the square lookups and rank edits.

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

Lookup: g2=black king; h1=empty.
Squares: g2 black king->empty; h1 empty->black king.
Ranks: rank 2 g k->1; rank 1 h 1->k.


Prompt:
Starting FEN: 8/1B3p2/8/6kp/1R4p1/4K3/5rP1/8 b - - 0 1
Move: f2a2
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 f2a2.
Lookup: f2=black rook; a2=empty.
Squares: f2 black rook->empty; a2 empty->black rook.
Ranks: rank 2 f r->1; rank 2 a 1->r.
Result FEN: 8/1B3p2/8/6kp/1R4p1/4K3/r5P1/8 w - - 1 2


Prompt:
Starting FEN: r2q1bnr/ppp1kbpp/3p1p2/1B1Pp2P/4P1P1/5Q2/PPP2P2/RNB1K2R w KQ - 0 1
Move: c1d2
Rewrite the affected compressed FEN rank rows and give Result FEN.
State needed for full FEN:
Side to move: white
Castling rights: KQ
En passant: none
Halfmove clock: 0
Fullmove number: 1

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

Rows: rank 1 RNB1K2R->RN2K2R; rank 2 PPP2P2->PPPB1P2.
Result FEN: r2q1bnr/ppp1kbpp/3p1p2/1B1Pp2P/4P1P1/5Q2/PPPB1P2/RN2K2R b KQ - 1 1


Prompt:
Starting FEN: r1bqk2r/bpp2p2/p1np1n2/4p1Np/P1B1P1P1/2PP3P/1P1N1P2/R1BQ1RK1 b kq - 0 1
After the moves f6g4, 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: 1

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

Result FEN: r1bqk2r/bpp2p2/p1np4/4p1Np/P1B1P1n1/2PP3P/1P1N1P2/R1BQ1RK1 w kq - 0 2


Prompt:
FEN: r3rqk1/pb1nn3/1p1p2pp/2pPp3/2P1P1P1/P1Q1BP2/1P2B1N1/R3K2R 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=c3; rook=a1,h1; bishop=e2,e3; knight=g2; pawn=b2,a3,f3,c4,e4,g4,d5.
Black inventory: king=g8; queen=f8; rook=a8,e8; bishop=b7; knight=d7,e7; pawn=c5,e5,b6,d6,g6,h6,a7.


Prompt:
FEN: r7/4kp1p/3p4/pP6/1n1PP2P/1P4K1/8/R4R2 w - - 5 34
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=0; pawn=5.
Black counts: king=1; queen=0; rook=1; bishop=0; knight=1; pawn=4.


Prompt:
FEN: r1bq1rk1/1p1pnpbp/p1n1p1p1/1Bp5/4PB2/2NP1N2/PPP2PPP/R2Q1RK1 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=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: r1b1k1n1/pppp1p1p/8/5p1Q/3qPP2/6P1/PPP4P/RN2KB1R w KQq - 0 14
Trace inventory, counts, values, and material balance.

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

Inventory: white king=e1; queen=h5; rook=a1,h1; bishop=f1; knight=b1; pawn=a2,b2,c2,h2,g3,e4,f4 | black king=e8; queen=d4; rook=a8; bishop=c8; knight=g8; pawn=f5,a7,b7,c7,d7,f7,h7
Counts: white king=1; queen=1; rook=2; bishop=1; knight=1; pawn=7 | black king=1; queen=1; rook=1; bishop=1; knight=1; pawn=7
Values: white total=32; black total=27
Balance: White is up 5 point(s) of material.


Prompt:
Starting FEN: 2r2rk1/1p2q2p/pb1p2p1/4np2/1Pb5/P1Q1PN2/1B2B1PP/R3K2R w KQ - 0 20
After the moves e3e4 f5e4, what is the resulting position?
State needed for full FEN:
Side to move: white
Castling rights: KQ
En passant: none
Halfmove clock: 0
Fullmove number: 20

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

Result FEN: 2r2rk1/1p2q2p/pb1p2p1/4n3/1Pb1p3/P1Q2N2/1B2B1PP/R3K2R w KQ - 0 21


Prompt:
Position (FEN): 6k1/6pp/p3p3/3p4/P2B1Pp1/P3P1K1/2rq3P/5RQ1 w - - 0 34
Show me the board.


r1bq1rk1/bpp2ppp/p1n5/3p4/B2PN3/5N1P/PP3PP1/R1BQR1K1 b - - 0 12

Prompt:
Here is the current board:
8 r . b q . r k .
7 b p p . . p p p
6 p . n . . . . .
5 . . . p . . . .
4 B . . P N . . .
3 . . . . . N . P
2 P 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: 12

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


Prompt:
FEN: rn1qk2r/p1p2ppp/1p1Bpn2/3p1b2/P1PP4/1Q2P3/1P3PPP/RN2KBNR b KQkq -
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: r1bqk2r/1p1nbppp/p2p1n2/4p3/4PP2/2NB1N2/PPP3PP/R1BQ1RK1 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: 8/1P4pk/8/Q3p2p/8/P6P/6PK/4r3 b - - 2 39
What is on g2?

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


Prompt:
FEN: 5rk1/2Q1np1p/5q2/5p2/P2P1P2/b1P4N/3r1PPP/1RR3K1 b - - 0 21
What is the compressed FEN row for rank 5?

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


Prompt:
FEN: r1bqk2r/pp1p1ppp/2n5/3Np3/4P1n1/6N1/PPPQ1bPP/R1BK1B1R w kq -
For square e6, 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>".

e6: file=e; rank=6; fen_row_from_top=3; file_index=5


Prompt:
FEN: r2q1rk1/1p4pp/p7/P1pp4/8/1P1P1n2/2P2p1P/R2K1QNR w - - 0 24
Compressed rank 6 row: p7
Expand it into file cells a through h.

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


r4rk1/pb1nqppp/1pp1pn2/3P4/3P4/1P1Q1NP1/P3PPBP/RN3RK1 b - - 0 11

Prompt:
Rank 5 row before: 3P4
File b changes from 1 to p. Rewrite the compressed row.

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


6rk/pb4rq/1pn1p3/2ppPpbP/5Q2/2PP3P/PP2NBBK/4R1R1 w - - 0 30

Prompt:
Board FEN before: 6rk/pb4rq/1pn1p3/2ppPpbP/5Q2/2PP3P/PP2NBBK/4R1R1
Apply square edits: f4 Q->1; g5 b->Q
Return the resulting board FEN only.

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

Result board FEN: 6rk/pb4rq/1pn1p3/2ppPpQP/8/2PP3P/PP2NBBK/4R1R1


Prompt:
Starting FEN: rn1qk2r/ppp1npbp/4b1p1/8/8/6P1/PPPP1PBP/RNBQK1NR w KQkq - 0 7
Move: g1e2
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 knight; e2=empty.
Squares: g1 white knight->empty; e2 empty->white knight.
Ranks: rank 1 g N->1; rank 2 e 1->N.


Prompt:
Starting FEN: r3kbnr/pppq1ppp/2n5/4p3/2BP4/1Q2PP2/PP3P1P/RNB1K2R w KQkq - 0 1
Move: h1f1
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 rook h1f1.
Lookup: h1=white rook; f1=empty.
Squares: h1 white rook->empty; f1 empty->white rook.
Ranks: rank 1 h R->1; rank 1 f 1->R.
Result FEN: r3kbnr/pppq1ppp/2n5/4p3/2BP4/1Q2PP2/PP3P1P/RNB1KR2 b Qkq - 1 1


Prompt:
Starting FEN: rnbq1rk1/5ppp/2pp1n2/ppb1p3/4P3/PB1P1N1P/1PP1NPP1/R1BQK2R b KQ - 0 9
Move: g7g5
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: 9

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

Rows: rank 7 5ppp->5p1p; rank 5 ppb1p3->ppb1p1p1.
Result FEN: rnbq1rk1/5p1p/2pp1n2/ppb1p1p1/4P3/PB1P1N1P/1PP1NPP1/R1BQK2R w KQ - 0 10


Prompt:
Starting FEN: rnbq1rk1/1p2ppb1/p2p1np1/8/2BNP2p/2N2P1P/PPPQ1BP1/R3K2R b KQ - 0 1
After the moves c8e6, 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: 1

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

Result FEN: rn1q1rk1/1p2ppb1/p2pbnp1/8/2BNP2p/2N2P1P/PPPQ1BP1/R3K2R w KQ - 1 2


Prompt:
FEN: r3k2r/pbq1bp2/1p1p2p1/4p2p/1PP2n2/P1B1Q1N1/5PPP/3RR1K1 b kq - 4 23
List the material inventory by side and piece type.

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

White inventory: king=g1; queen=e3; rook=d1,e1; bishop=c3; knight=g3; pawn=f2,g2,h2,a3,b4,c4.
Black inventory: king=e8; queen=c7; rook=a8,h8; bishop=b7,e7; knight=f4; pawn=e5,h5,b6,d6,g6,a7,f7.


Prompt:
FEN: 7r/1pp5/p2p1k1r/4p3/3n2B1/3P1P2/PPP3P1/R4RK1 w - - 1 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=0; rook=2; bishop=1; knight=0; pawn=6.
Black counts: king=1; queen=0; rook=2; bishop=0; knight=1; pawn=5.


Prompt:
FEN: 3Q4/5pk1/4p3/8/p6P/6P1/5P2/q5K1 w - - 1 52
Convert the piece counts into material value totals.

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

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


Prompt:
FEN: rnb2rk1/4qpp1/p2p1n1p/1ppP4/1bP5/2N2PN1/PPQB2PP/2KR1B1R w - -
Trace inventory, counts, values, and material balance.

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

Inventory: white king=c1; queen=c2; rook=d1,h1; bishop=f1,d2; knight=c3,g3; pawn=a2,b2,g2,h2,f3,c4,d5 | black king=g8; queen=e7; rook=a8,f8; bishop=b4,c8; knight=f6,b8; pawn=b5,c5,a6,d6,h6,f7,g7
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: 7k/ppp5/3p1N1P/r7/1K6/1P1R1p2/P1P5/1r4q1 b - - 5 35
After the moves b1c1 d3e3 g1f1, what is the resulting position?
State needed for full FEN:
Side to move: black
Castling rights: none
En passant: none
Halfmove clock: 5
Fullmove number: 35

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


Prompt:
Position (FEN): r2qkb1r/ppp2ppp/2npbn2/1B2p3/4P3/2P2N1P/PP1P1PP1/RNBQ1RK1 w kq -
Show me the board.

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


Prompt:
Here is the current board:
8 . r . . . . . .
7 q . p k . p p .
6 P . . . p . b p
5 . . . r . . . .
4 . P . . . . . .
3 . . Q . . . . P
2 . . . . . 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: 5
Fullmove number: 31

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


Prompt:
FEN: 2r1k1r1/p2q1p1p/Q3pBp1/3pPn2/1p4P1/P1N5/1PP2P1P/R4RK1 b - - 0 21
What piece is on g4?

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


Prompt:
FEN: 4r1k1/2P3p1/7p/5p1P/5P2/8/R1PK2P1/8 b - - 0 44
What is the material count for both sides?

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


Prompt:
FEN: 5k2/6r1/4Q3/8/8/8/6K1/8 w - -
What is on d5?

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


Prompt:
FEN: r2q1rk1/p3bppp/2p1pn2/2pp4/5P2/1P1PPb1P/PBPN2P1/R2Q1RK1 w - -
What is the compressed FEN row for rank 7?

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


Prompt:
FEN: 5k1r/p1p2ppp/5n2/8/8/1nP1BB2/4KPPP/7R b - -
For square a7, give the FEN row-from-top and file index.

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

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


Prompt:
FEN: 7k/8/7P/7K/6P1/8/8/8 b - - 2 67
Compressed rank 4 row: 6P1
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: 2P1P2P
File c changes from P to 1. Rewrite the compressed row.

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


Prompt:
Board FEN before: 2r1r3/5kp1/b4p1p/p1p4R/2P5/3B4/PPK3PP/3R4
Apply square edits: d1 R->1; c1 1->R
Return the resulting board FEN only.

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

Result board FEN: 2r1r3/5kp1/b4p1p/p1p4R/2P5/3B4/PPK3PP/2R5


Prompt:
Starting FEN: 8/2k5/2B5/2K5/8/1N6/8/8 b - -
Move: c7d8
List the square lookups and rank edits.

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

Lookup: c7=black king; d8=empty.
Squares: c7 black king->empty; d8 empty->black king.
Ranks: rank 7 c k->1; rank 8 d 1->k.


Prompt:
Starting FEN: 3r2k1/5p2/2B3pp/p3p3/Pp1b4/3K3P/R5P1/8 b - - 1 37
Move: e5e4
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: 37

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

Move 1: black pawn e5e4.
Lookup: e5=black pawn; e4=empty.
Squares: e5 black pawn->empty; e4 empty->black pawn.
Ranks: rank 5 e p->1; rank 4 e 1->p.
Result FEN: 3r2k1/5p2/2B3pp/p7/Pp1bp3/3K3P/R5P1/8 w - - 0 38


Prompt:
Starting FEN: rnbqk2r/pppp2pp/4p3/5p2/2PPn3/2P2NP1/P3PP1P/R1BQKB1R w KQkq - 0 1
Move: c1h6
Rewrite the affected compressed FEN rank rows and give Result FEN.
State needed for full FEN:
Side to move: white
Castling rights: KQkq
En passant: none
Halfmove clock: 0
Fullmove number: 1

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

Rows: rank 1 R1BQKB1R->R2QKB1R; rank 6 4p3->4p2B.
Result FEN: rnbqk2r/pppp2pp/4p2B/5p2/2PPn3/2P2NP1/P3PP1P/R2QKB1R b KQkq - 1 1


Prompt:
Starting FEN: 6k1/1p3p1p/2q5/p3Q1p1/2P5/PP2R2P/2P3P1/6K1 b - - 1 28
After the moves c6b6, 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: 28

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


Prompt:
FEN: 2kr2nr/pbpq2bp/1p1p2p1/3Ppn2/2P1B3/2N2P2/PP2NBPP/R2Q1RK1 w - - 1 15
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=f2,e4; knight=e2,c3; pawn=a2,b2,g2,h2,f3,c4,d5.
Black inventory: king=c8; queen=d7; rook=d8,h8; bishop=b7,g7; knight=f5,g8; pawn=e5,b6,d6,g6,a7,c7,h7.


Prompt:
FEN: 2kr1bnr/pbq2ppp/1pn5/2p1p3/1P1pP3/P1NB1N2/1BPP1PPP/R2Q1RK1 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=2; knight=2; pawn=8.
Black counts: king=1; queen=1; rook=2; bishop=2; knight=2; pawn=8.


Prompt:
FEN: r1bq1rk1/pp1nbppp/8/4p1P1/4P2P/2NP4/PP1Q4/R3KBNR 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=6; pawn=6; total=34.
Black values: king=0; queen=9; rook=10; bishop=6; knight=3; pawn=6; total=34.


Prompt:
FEN: r1bq1rk1/p1b2ppp/2p5/2P1P3/3Pp3/4B3/P5PP/RN1Q1RK1 b - - 1 15
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=e3; knight=b1; pawn=a2,g2,h2,d4,c5,e5 | black king=g8; queen=d8; rook=a8,f8; bishop=c7,c8; knight=none; pawn=e4,c6,a7,f7,g7,h7
Counts: white king=1; queen=1; rook=2; bishop=1; knight=1; pawn=6 | black king=1; queen=1; rook=2; bishop=2; knight=0; pawn=6
Values: white total=31; black total=31
Balance: Material is equal.


Prompt:
Starting FEN: rnbqkb1r/pp3ppp/3ppn2/2p3N1/2B1P3/2N5/PPPP1PPP/R1BQK2R b KQkq - 1 5
After the moves a7a6 d1f3 a8a7, 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: 5

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

Result FEN: 1nbqkb1r/rp3ppp/p2ppn2/2p3N1/2B1P3/2N2Q2/PPPP1PPP/R1B1K2R w KQk - 2 7


Prompt:
Position (FEN): 1rb2rk1/1p3ppp/p1n5/2qNp3/P3P3/2PP2P1/2P2PBP/1R1Q1RK1 w - - 6 20
Show me the board.


r2qk2r/1pp1b1pp/p2p1np1/3Pp3/2P1N3/1P2PQ1P/P4PP1/R1B1K2R b KQkq - 0 12

Prompt:
Here is the current board:
8 r . . q k . . r
7 . p p . b . p p
6 p . . p . n p .
5 . . . P p . . .
4 . . P . N . . .
3 . P . . P Q . P
2 P . . . . P P .
1 R . B . K . . 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: 12

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


Prompt:
FEN: 6k1/2r5/p4pNp/1p1p1p1P/1P1P1P2/4P3/1B1K3R/8 w - - 1 32
What piece is on b4?

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


Prompt:
FEN: r1bq1rk1/1p2ppbp/n2p1np1/p7/3B4/1P2PNP1/P1PN1PBP/R2Q1RK1 b - - 0 10
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: rnbqkbnr/1pp2ppp/p2p4/3Pp3/4P3/2N2N1P/PPP2PP1/R1BQKB1R b KQkq - 0 6
What is on d1?

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


Prompt:
FEN: 5k1r/4b1p1/p2qQp1p/1p1p4/3P4/1P5P/P3RP1P/R5K1 w - - 6 28
What is the compressed FEN row for rank 3?

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


Prompt:
FEN: 8/4bppk/2Q1pq1p/1rP5/3P4/R3B3/5PPP/5RK1 b - - 0 26
For square d7, give the FEN row-from-top and file index.

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

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


Prompt:
FEN: r2qk1nr/ppp2ppp/2n5/3pN3/Qb1P2b1/2N5/PP2PPPP/R1B1KB1R b KQkq -
Compressed rank 6 row: 2n5
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: 6r1
File f changes from 1 to Q. Rewrite the compressed row.

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


Prompt:
Board FEN before: 8/3Q4/4k3/4N3/1p6/p7/K7/4q3
Apply square edits: e6 k->1; f6 1->k
Return the resulting board FEN only.

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

Result board FEN: 8/3Q4/5k2/4N3/1p6/p7/K7/4q3


Prompt:
Starting FEN: 1r2k3/p2n2p1/2p1ppp1/2Np2Pr/3P1P2/1P2P2P/P2K4/R6R b - - 1 21
Move: h5h8
List the square lookups and rank edits.

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

Lookup: h5=black rook; h8=empty.
Squares: h5 black rook->empty; h8 empty->black rook.
Ranks: rank 5 h r->1; rank 8 h 1->r.


Prompt:
Starting FEN: 8/1p6/2b5/4k3/5nPp/1R3P1P/5R1K/r7 b - - 0 1
Move: a1f1
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 a1f1.
Lookup: a1=black rook; f1=empty.
Squares: a1 black rook->empty; f1 empty->black rook.
Ranks: rank 1 a r->1; rank 1 f 1->r.
Result FEN: 8/1p6/2b5/4k3/5nPp/1R3P1P/5R1K/5r2 w - - 1 2


Prompt:
Starting FEN: 1r6/4pqbk/pn1p2pp/1p6/3P1r1N/2PQ1N1P/PPB2P2/2KR4 w - - 0 1
Move: h4g6
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 3P1r1N->3P1r2; rank 6 pn1p2pp->pn1p2Np.
Result FEN: 1r6/4pqbk/pn1p2Np/1p6/3P1r2/2PQ1N1P/PPB2P2/2KR4 b - - 0 1


Prompt:
Starting FEN: r4rk1/pp4pp/2pbbpn1/q1n1p3/1P2P3/2P1NNP1/P1Q2PBP/R1B1R1K1 b - - 0 1
After the moves d6e7, 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/pp2b1pp/2p1bpn1/q1n1p3/1P2P3/2P1NNP1/P1Q2PBP/R1B1R1K1 w - - 1 2


Prompt:
FEN: 8/8/8/p1p5/1pPpk3/1P6/P3K3/8 b - - 3 52
List the material inventory by side and piece type.

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

White inventory: king=e2; queen=none; rook=none; bishop=none; knight=none; pawn=a2,b3,c4.
Black inventory: king=e4; queen=none; rook=none; bishop=none; knight=none; pawn=b4,d4,a5,c5.


Prompt:
FEN: r3r1k1/p4p2/5n1p/3pbq2/2p5/2N4P/PP1Q1PP1/R3R1K1 b - - 3 22
Count each piece type for both sides.

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

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


Prompt:
FEN: r2q1rk1/pp3pbp/2n1pn2/3p1p2/3P1B2/2P2N1P/PP3PP1/RN1QR1K1 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=10; bishop=3; knight=6; pawn=7; total=35.
Black values: king=0; queen=9; rook=10; bishop=3; knight=6; pawn=7; total=35.


Prompt:
FEN: rnbq1rk1/ppp2pbp/3p1np1/4p1B1/4P3/2NP1N2/PPP1BPPP/R2Q1RK1 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=e2,g5; knight=c3,f3; pawn=a2,b2,c2,f2,g2,h2,d3,e4 | black king=g8; queen=d8; rook=a8,f8; bishop=g7,c8; knight=f6,b8; pawn=e5,d6,g6,a7,b7,c7,f7,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: r4rk1/1ppb2pp/p2bpq2/3p1p2/3P4/4P1N1/PPP2PPP/R2QKB1R w KQ - 4 11
After the moves h1g1 d6b4, what is the resulting position?
State needed for full FEN:
Side to move: white
Castling rights: KQ
En passant: none
Halfmove clock: 4
Fullmove number: 11

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

Result FEN: r4rk1/1ppb2pp/p3pq2/3p1p2/1b1P4/4P1N1/PPP2PPP/R2QKBR1 w Q - 6 12


Prompt:
Position (FEN): 2r2k2/5p2/p6r/6p1/2nPR2p/2P3q1/1P4N1/2R1Q1K1 w - - 0 38
Show me the board.


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

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

rn1qk2r/pb1pbppp/1p2pn2/2p5/2P5/1P2PN2/PB1PBPPP/RN1QK2R w KQkq - 0 1


Prompt:
FEN: r2qrbk1/1b3p2/p1n2npp/1P1pp3/1P2P3/3P1NN1/2BB1PPP/R2QR1K1 b - -
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: 8/5p2/5b1p/3k4/3P1PPP/4K3/8/8 b - -
What is the material count for both sides?

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


Prompt:
FEN: 2K5/7q/4k3/8/8/8/8/8 b - - 23 91
What is on f3?

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


Prompt:
FEN: r3kbnr/ppp2ppp/2n5/4p2q/6b1/2NP1N2/PPP1BPPP/R1BQK2R w KQkq -
What is the compressed FEN row for rank 7?

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


Prompt:
FEN: R6R/8/8/1k6/p7/6P1/P2BrPKP/8 w - - 5 41
For square f4, 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>".

f4: file=f; rank=4; fen_row_from_top=5; file_index=6


Prompt:
FEN: r2q1rk1/1ppnppbp/3p2p1/p2P4/PnP5/1PN2BP1/1B2PP1P/R2Q1RK1 w - -
Compressed rank 7 row: 1ppnppbp
Expand it into file cells a through h.

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

rank 7: a=1; b=p; c=p; d=n; e=p; f=p; g=b; h=p


r2qk2r/2p1bppp/p3b3/1p6/1P1BQP2/P1N1P3/6PP/R3K2R w KQkq -

Prompt:
Rank 5 row before: 1p6
File b changes from p to N. Rewrite the compressed row.

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


Prompt:
Board FEN before: 6k1/6pp/p7/3rp3/P3P3/2K1n3/8/8
Apply square edits: a4 P->1; a5 1->P
Return the resulting board FEN only.

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

Result board FEN: 6k1/6pp/p7/P2rp3/4P3/2K1n3/8/8


Prompt:
Starting FEN: r2qk2r/1p1b1p2/3p4/p1pN2p1/P1PpP2p/1P1P1P2/2K1B1PP/1R3R2 b kq - 3 24
Move: h8f8
List the square lookups and rank edits.

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

Lookup: h8=black rook; f8=empty.
Squares: h8 black rook->empty; f8 empty->black rook.
Ranks: rank 8 h r->1; rank 8 f 1->r.


Prompt:
Starting FEN: 2k4r/pp3ppp/1b6/4pP2/q1p1P3/2PrB3/1Q2R1PP/1R5K b - - 3 23
Move: a7a6
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: 3
Fullmove number: 23

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

Move 1: black pawn a7a6.
Lookup: a7=black pawn; a6=empty.
Squares: a7 black pawn->empty; a6 empty->black pawn.
Ranks: rank 7 a p->1; rank 6 a 1->p.
Result FEN: 2k4r/1p3ppp/pb6/4pP2/q1p1P3/2PrB3/1Q2R1PP/1R5K w - - 0 24


Prompt:
Starting FEN: 6k1/p3K1Pp/7q/P7/8/5b2/8/8 w - - 0 53
Move: e7e8
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: 53

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


Prompt:
Starting FEN: 5rk1/n1r2ppp/1p1p2q1/p7/4P3/R1B2P2/1PP2QPP/4R1K1 b - - 7 23
After the moves g6f6, what is the resulting position?
State needed for full FEN:
Side to move: black
Castling rights: none
En passant: none
Halfmove clock: 7
Fullmove number: 23

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

Result FEN: 5rk1/n1r2ppp/1p1p1q2/p7/4P3/R1B2P2/1PP2QPP/4R1K1 w - - 8 24


Prompt:
FEN: r2q3r/p1pkpQ1p/8/1p1p4/4b1P1/2N3PP/PP1K1R2/nN6 b - - 1 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=d2; queen=f7; rook=f2; bishop=none; knight=b1,c3; pawn=a2,b2,g3,h3,g4.
Black inventory: king=d7; queen=d8; rook=a8,h8; bishop=e4; knight=a1; pawn=b5,d5,a7,c7,e7,h7.


Prompt:
FEN: rn1qkb1r/1bp1pppp/p4n2/1p6/3P4/3BPN2/PP3PPP/RNBQK2R w KQkq -
Count each piece type for both sides.

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

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


Prompt:
FEN: 1k1r4/2p5/2p2p2/1P6/P1P1pPr1/3pP3/5P1P/R2R1K2 b - -
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=0; pawn=7; total=17.
Black values: king=0; queen=0; rook=10; bishop=0; knight=0; pawn=5; total=15.


Prompt:
FEN: 5k2/p3Npr1/1p5Q/4p3/2p1P3/b2P4/2R2PPP/5RK1 w - - 0 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=h6; rook=f1,c2; bishop=none; knight=e7; pawn=f2,g2,h2,d3,e4 | black king=f8; queen=none; rook=g7; bishop=a3; knight=none; pawn=c4,e5,b6,a7,f7
Counts: white king=1; queen=1; rook=2; bishop=0; knight=1; pawn=5 | black king=1; queen=0; rook=1; bishop=1; knight=0; pawn=5
Values: white total=27; black total=13
Balance: White is up 14 point(s) of material.


Prompt:
Starting FEN: 3k4/2R5/2P3pp/5p2/5P1K/2r3PP/8/8 w - - 2 38
After the moves c7h7 c3f3, 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: 38

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


Prompt:
Position (FEN): 8/p2b1pk1/4p1p1/8/1N6/P7/1P1K3P/8 w - -
Show me the board.


r3kbnr/pppq1ppp/2n1p3/1B1p1b2/3P1B2/4PN2/PPP2PPP/RN1QK2R w KQkq - 2 6

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

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


Prompt:
FEN: rnb1kbnr/ppp2ppp/8/4p3/4P3/8/PPP1NPPP/RNBqKB1R w KQkq -
What piece is on d1?

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


Prompt:
FEN: r1b1k2r/p2n1ppp/1pn1p3/1B2P3/1b6/2N2N2/PP4PP/R1BK3R b kq - 2 12
What is the material count for both sides?

White (12 pieces): 2 bishops, 1 king, 2 knights, 5 pawns, 2 rooks. Black (13 pieces): 2 bishops, 1 king, 2 knights, 6 pawns, 2 rooks. Black is up 1 point(s) of material.


Prompt:
FEN: r1bqk1nr/pppn1p1p/6p1/4b3/2P1P3/2N5/PP4PP/R1BQKBNR w KQkq -
What is on b3?

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


Prompt:
FEN: r6r/3knpb1/3p1p1p/p1pPp3/Pp2P3/1P1P1NP1/5P1P/R3KB1R w KQ - 0 17
What is the compressed FEN row for rank 8?

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


Prompt:
FEN: 2r3rk/p5pp/bq5N/2b1p3/3nP3/4B2P/P4PP1/6K1 w - -
For square e5, 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>".

e5: file=e; rank=5; fen_row_from_top=4; file_index=5


Prompt:
FEN: 1r3rk1/p6p/4pp2/4q1P1/2Qp1n2/3P4/PP1B2P1/R2K3R w - - 0 23
Compressed rank 1 row: R2K3R
Expand it into file cells a through h.

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


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

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


Prompt:
Board FEN before: 6k1/2p2pp1/2n1p2p/2P1P3/6r1/Q6K/5P1P/3q2R1
Apply square edits: c6 n->1; d8 1->n
Return the resulting board FEN only.

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

Result board FEN: 3n2k1/2p2pp1/4p2p/2P1P3/6r1/Q6K/5P1P/3q2R1


Prompt:
Starting FEN: r1bqk1nr/1p1nbp1p/4p1p1/pP1pP3/6Q1/P4N2/2P2PPP/RNB1KB1R w KQkq -
Move: f3g1
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; g1=empty.
Squares: f3 white knight->empty; g1 empty->white knight.
Ranks: rank 3 f N->1; rank 1 g 1->N.


Prompt:
Starting FEN: r1bq1r1k/ppp1n1pp/1b1P4/6p1/4R3/1QN2N1P/PP3PP1/R5K1 w - - 0 1
Move: c3a4
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 c3a4.
Lookup: c3=white knight; a4=empty.
Squares: c3 white knight->empty; a4 empty->white knight.
Ranks: rank 3 c N->1; rank 4 a 1->N.
Result FEN: r1bq1r1k/ppp1n1pp/1b1P4/6p1/N3R3/1Q3N1P/PP3PP1/R5K1 b - - 1 1


Prompt:
Starting FEN: 4r1rk/6pp/pN1p4/1p1R4/5P2/1Q2BK2/PPP4q/8 b - - 2 32
Move: h2h6
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: 2
Fullmove number: 32

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

Rows: rank 2 PPP4q->PPP5; rank 6 pN1p4->pN1p3q.
Result FEN: 4r1rk/6pp/pN1p3q/1p1R4/5P2/1Q2BK2/PPP5/8 w - - 3 33


Prompt:
Starting FEN: rn2q1k1/p4p1p/1pp3p1/3n2N1/3P2b1/1BP5/P2B1PPP/1R2K2R w K - 0 18
After the moves g5e6, what is the resulting position?
State needed for full FEN:
Side to move: white
Castling rights: K
En passant: none
Halfmove clock: 0
Fullmove number: 18

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

Result FEN: rn2q1k1/p4p1p/1pp1N1p1/3n4/3P2b1/1BP5/P2B1PPP/1R2K2R b K - 1 18


Prompt:
FEN: r6r/ppkn1P1p/8/3p4/1PpP2p1/6P1/PP1N3P/R4RK1 w - - 1 23
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,f1; bishop=none; knight=d2; pawn=a2,b2,h2,g3,b4,d4,f7.
Black inventory: king=c7; queen=none; rook=a8,h8; bishop=none; knight=d7; pawn=c4,g4,d5,a7,b7,h7.


Prompt:
FEN: rn2k1nr/1b1p2pp/p2bp3/1p2Npq1/3P4/3BP3/PP1B1PPP/RN1Q1RK1 w kq - 2 12
Count each piece type for both sides.

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

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


Prompt:
FEN: rn1qk2r/1p3ppp/p2pbn2/2b1p3/2P5/2NBP3/PPQ1NPPP/R1B1K2R 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=7; total=38.
Black values: king=0; queen=9; rook=10; bishop=6; knight=6; pawn=7; total=38.


Prompt:
FEN: 2k5/1p3p2/5p2/3r1P2/3p4/3PpKB1/2P5/5R2 w - -
Trace inventory, counts, values, and material balance.

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

Inventory: white king=f3; queen=none; rook=f1; bishop=g3; knight=none; pawn=c2,d3,f5 | black king=c8; queen=none; rook=d5; bishop=none; knight=none; pawn=e3,d4,f6,b7,f7
Counts: white king=1; queen=0; rook=1; bishop=1; knight=0; pawn=3 | black king=1; queen=0; rook=1; bishop=0; knight=0; pawn=5
Values: white total=11; black total=10
Balance: White is up 1 point(s) of material.


Prompt:
Starting FEN: r2q2k1/ppp2pp1/3pr2p/3n3Q/4PR2/P2P4/1PP3PP/R5K1 w - - 0 17
After the moves a3a4 d5c3, 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: 17

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

Result FEN: r2q2k1/ppp2pp1/3pr2p/7Q/P3PR2/2nP4/1PP3PP/R5K1 w - - 1 18


Prompt:
Position (FEN): rn2k1nr/1bqp1ppp/ppp1p3/8/1bPPP3/2N1B3/PP1QBPPP/2KR2NR b kq - 5 8
Show me the board.

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


rnb2rk1/ppb2pp1/2p1pq1p/2Pp4/1P1P4/P4N1P/4PPP1/RN1QKB1R w KQ - 0 10

Prompt:
Here is the current board:
8 r n b . . r k .
7 p p b . . p p .
6 . . p . p q . p
5 . . P p . . . .
4 . P . P . . . .
3 P . . . . N . P
2 . . . . P P P .
1 R N . Q 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: white
Castling rights: KQ
En passant: none
Halfmove clock: 0
Fullmove number: 10

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


Prompt:
FEN: 8/8/8/8/3Q4/2K5/6k1/8 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: 7k/1pp3pp/p7/2P3K1/6PP/P2pP3/8/5r2 b - - 0 37
What is the material count for both sides?

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


Prompt:
FEN: 4k2r/1b2bppp/pN1p4/5P2/4n1q1/1PN5/P2R2PP/R1B3K1 w - - 3 21
What is on e3?

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


Prompt:
FEN: r1b2rk1/pp4p1/4p2p/3pnpNQ/3q3R/P2B4/2P3PP/1R5K b - - 1 19
What is the compressed FEN row for rank 3?

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


Prompt:
FEN: rn2kbnr/pb1p2q1/1pp1pp1p/6p1/2PPPP2/2N1BN2/PP1QB1PP/2KR3R w kq - 0 11
For square d7, give the FEN row-from-top and file index.

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

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


Prompt:
FEN: r1b3k1/pp1p1p2/1b4p1/n1pr2BQ/8/8/PP3PPP/R3R1K1 w - -
Compressed rank 4 row: 8
Expand it into file cells a through h.

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


Prompt:
Rank 8 row before: r4Rk1
File a changes from r to 1. Rewrite the compressed row.

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


Prompt:
Board FEN before: 3R4/8/4N3/4k3/8/5Q2/8/2b2K2
Apply square edits: c1 b->1; f4 1->b
Return the resulting board FEN only.

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


Prompt:
Starting FEN: rn2kb1r/ppq1npp1/2p1p3/P2pPb1p/3P3P/2P2N2/1P2BPP1/RNBQK2R b KQkq -
Move: c6c5
List the square lookups and rank edits.

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

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


Prompt:
Starting FEN: rnbqkb1r/ppp2ppp/4pn2/3pN3/3P1B2/8/PPP1PPPP/RN1QKB1R b KQkq - 0 1
Move: g7g6
Use square lookups and rank edits to assemble the resulting full FEN.
State needed for full FEN:
Side to move: black
Castling rights: KQkq
En passant: none
Halfmove clock: 0
Fullmove number: 1

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

Move 1: black pawn g7g6.
Lookup: g7=black pawn; g6=empty.
Squares: g7 black pawn->empty; g6 empty->black pawn.
Ranks: rank 7 g p->1; rank 6 g 1->p.
Result FEN: rnbqkb1r/ppp2p1p/4pnp1/3pN3/3P1B2/8/PPP1PPPP/RN1QKB1R w KQkq - 0 2


Prompt:
Starting FEN: rnb1k2r/pp1pppb1/1qp3pn/8/3PP3/2P5/PP3PP1/RNBQKBNR w KQkq - 0 1
Move: d1g4
Rewrite the affected compressed FEN rank rows and give Result FEN.
State needed for full FEN:
Side to move: white
Castling rights: KQkq
En passant: none
Halfmove clock: 0
Fullmove number: 1

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

Rows: rank 1 RNBQKBNR->RNB1KBNR; rank 4 3PP3->3PP1Q1.
Result FEN: rnb1k2r/pp1pppb1/1qp3pn/8/3PP1Q1/2P5/PP3PP1/RNB1KBNR b KQkq - 1 1


Prompt:
Starting FEN: rn1qkbnr/pp3ppb/2p4p/3pPp2/3P2P1/2NB4/PPP4P/R1BQK1NR w KQkq - 0 9
After the moves e1f2, 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: 9

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

Result FEN: rn1qkbnr/pp3ppb/2p4p/3pPp2/3P2P1/2NB4/PPP2K1P/R1BQ2NR b kq - 1 9


Prompt:
FEN: r1b1k2r/1pq1b3/p3p2p/3pP1p1/2pQ4/P1P3BP/1P3PP1/RB3RK1 b kq - 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=g1; queen=d4; rook=a1,f1; bishop=b1,g3; knight=none; pawn=b2,f2,g2,a3,c3,h3,e5.
Black inventory: king=e8; queen=c7; rook=a8,h8; bishop=e7,c8; knight=none; pawn=c4,d5,g5,a6,e6,h6,b7.


Prompt:
FEN: 6k1/pp3pb1/2p1bn1p/4p3/2P1Pp2/1PNB1N1P/P4PP1/6K1 b - - 0 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=0; rook=0; bishop=1; knight=2; pawn=7.
Black counts: king=1; queen=0; rook=0; bishop=2; knight=1; pawn=7.


Prompt:
FEN: 2rr1k2/pb3ppQ/1p2N3/2q5/7P/2P1nP2/PP4P1/2KR3R b - -
Convert the piece counts into material value totals.

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

White values: king=0; queen=9; rook=10; bishop=0; knight=3; pawn=6; total=28.
Black values: king=0; queen=9; rook=10; bishop=3; knight=3; pawn=4; total=29.


Prompt:
FEN: r3r1k1/pp2nppp/2n1p3/3pP3/3PbPP1/B1P4P/P2N1K2/R5R1 w - - 4 18
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=a1,g1; bishop=a3; knight=d2; pawn=a2,c3,h3,d4,f4,g4,e5 | black king=g8; queen=none; rook=a8,e8; bishop=e4; knight=c6,e7; pawn=d5,e6,a7,b7,f7,g7,h7
Counts: white king=1; queen=0; rook=2; bishop=1; knight=1; pawn=7 | black king=1; queen=0; rook=2; bishop=1; knight=2; pawn=7
Values: white total=23; black total=26
Balance: Black is up 3 point(s) of material.


Prompt:
Starting FEN: 7R/8/4K3/3r1p2/4b3/4k3/8/8 b - - 17 58
After the moves e4c2 h8h5, what is the resulting position?
State needed for full FEN:
Side to move: black
Castling rights: none
En passant: none
Halfmove clock: 17
Fullmove number: 58

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


Prompt:
Position (FEN): 8/8/3K4/3B4/3B1k2/8/8/8 w - -
Show me the board.


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

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


Prompt:
FEN: q5k1/5pp1/8/1pb1P3/1Pp4p/2P2r2/5PQ1/1N3RK1 b - b3
What piece is on c3?

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: rn1q1rk1/pbppppbp/1p4p1/3nP3/3P4/5NB1/PPPN1PPP/R2QKB1R w KQ -
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: 3R4/6r1/5K2/3b4/3k1P2/8/8/8 b - -
What is on d5?

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


Prompt:
FEN: rnbqk2r/ppp2ppp/5n2/3Pp3/2p1P3/2P5/P4PPP/R1BQKBNR w KQkq -
What is the compressed FEN row for rank 5?

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


Prompt:
FEN: 8/5k2/3R4/2K5/8/8/8/8 w - -
For square d4, give the FEN row-from-top and file index.

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

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


Prompt:
FEN: 8/p1k5/1p2r3/3p4/3p4/2P1N2P/PP2K1P1/8 w - - 0 39
Compressed rank 5 row: 3p4
Expand it into file cells a through h.

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


Prompt:
Rank 1 row before: 4R2K
File f changes from 1 to R. Rewrite the compressed row.

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


Prompt:
Board FEN before: 8/1p1k1ppp/1Pp1p3/3p1b2/3P4/r3P3/4BPPP/5RK1
Apply square edits: e2 B->1; d3 1->B
Return the resulting board FEN only.

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

Result board FEN: 8/1p1k1ppp/1Pp1p3/3p1b2/3P4/r2BP3/5PPP/5RK1


Prompt:
Starting FEN: r2qkb1r/pp1bppp1/3p1n2/7p/3nP3/2N1BP2/PPPQ2PP/R3KB1R w KQkq -
Move: e1f2
List the square lookups and rank edits.

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

Lookup: e1=white king; f2=empty.
Squares: e1 white king->empty; f2 empty->white king.
Ranks: rank 1 e K->1; rank 2 f 1->K.


Prompt:
Starting FEN: r2q1rk1/pb3pb1/4pn1p/3p2p1/8/2NB2B1/PPP2PPP/R2QR1K1 b - - 3 15
Move: d5d4
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: 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 d5d4.
Lookup: d5=black pawn; d4=empty.
Squares: d5 black pawn->empty; d4 empty->black pawn.
Ranks: rank 5 d p->1; rank 4 d 1->p.
Result FEN: r2q1rk1/pb3pb1/4pn1p/6p1/3p4/2NB2B1/PPP2PPP/R2QR1K1 w - - 0 16


Prompt:
Starting FEN: r3kbnr/1ppq2pp/p1p1bp2/4p3/4P3/5N1P/PPPP1PP1/RNBQR1K1 w kq - 4 8
Move: g2g3
Rewrite the affected compressed FEN rank rows and give Result FEN.
State needed for full FEN:
Side to move: white
Castling rights: kq
En passant: none
Halfmove clock: 4
Fullmove number: 8

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

Rows: rank 2 PPPP1PP1->PPPP1P2; rank 3 5N1P->5NPP.
Result FEN: r3kbnr/1ppq2pp/p1p1bp2/4p3/4P3/5NPP/PPPP1P2/RNBQR1K1 b kq - 0 8


Prompt:
Starting FEN: rnbqk1nr/pp3pbp/2pp2p1/8/3P4/2N1P3/PP3PPP/R1BQKBNR b KQkq - 1 6
After the moves c8e6, 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: 6

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

Result FEN: rn1qk1nr/pp3pbp/2ppb1p1/8/3P4/2N1P3/PP3PPP/R1BQKBNR w KQkq - 2 7


Prompt:
FEN: r1bq1rk1/pp1nbp1p/2p1p1p1/3pPn2/3P1P2/2N2N2/PPPBQ1PP/2KR1B1R w - - 7 10
List the material inventory by side and piece type.

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

White inventory: king=c1; queen=e2; rook=d1,h1; bishop=f1,d2; knight=c3,f3; pawn=a2,b2,c2,g2,h2,d4,f4,e5.
Black inventory: king=g8; queen=d8; rook=a8,f8; bishop=e7,c8; knight=f5,d7; pawn=d5,c6,e6,g6,a7,b7,f7,h7.


Prompt:
FEN: 3k4/8/8/2n5/R7/7P/6PK/8 w - - 1 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=1; bishop=0; knight=0; pawn=2.
Black counts: king=1; queen=0; rook=0; bishop=0; knight=1; pawn=0.


Prompt:
FEN: rnbq1rk1/ppp2ppp/3b1n2/3Pp3/2B5/2N2N2/PPPP1PPP/R1BQK2R w KQ -
Convert the piece counts into material value totals.

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

White values: king=0; queen=9; rook=10; bishop=6; knight=6; pawn=8; total=39.
Black values: king=0; queen=9; rook=10; bishop=6; knight=6; pawn=7; total=38.


Prompt:
FEN: 8/1q4pk/3r2p1/7p/4QP2/1P4P1/4R2P/5K2 b - -
Trace inventory, counts, values, and material balance.

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

Inventory: white king=f1; queen=e4; rook=e2; bishop=none; knight=none; pawn=h2,b3,g3,f4 | black king=h7; queen=b7; rook=d6; bishop=none; knight=none; pawn=h5,g6,g7
Counts: white king=1; queen=1; rook=1; bishop=0; knight=0; pawn=4 | black king=1; queen=1; rook=1; bishop=0; knight=0; pawn=3
Values: white total=18; black total=17
Balance: White is up 1 point(s) of material.


Prompt:
Starting FEN: 8/1b3pkp/1p1q1np1/pB1p4/3N4/P1P4P/1P2QPP1/6K1 w - - 2 29
After the moves b2b3 d6e5 f2f4, 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: 29

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

Result FEN: 8/1b3pkp/1p3np1/pB1pq3/3N1P2/PPP4P/4Q1P1/6K1 b - - 0 30


Prompt:
Position (FEN): 8/8/5k2/4p3/5p2/r4K2/8/1R6 w - -
Show me the board.


Prompt:
Here is the current board:
8 . . . q . . . r
7 . p . k . p p .
6 . . . N . . . .
5 . . B . P . . .
4 P . . . . P . p
3 . . P . Q . n P
2 . . . . . . 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: 5
Fullmove number: 27

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


Prompt:
FEN: r2q1rk1/pp2bppp/2npbn2/2p1p3/2B1P3/2NPNP2/PPP3PP/R1BQ1RK1 b - -
What piece is on c6?

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


Prompt:
FEN: k5nr/p2B3p/3Bp1p1/p2pp3/3P1P2/1qP5/P5PP/5RK1 w - - 0 28
What is the material count for both sides?

White (10 pieces): 2 bishops, 1 king, 6 pawns, 1 rook. Black (11 pieces): 1 king, 1 knight, 7 pawns, 1 queen, 1 rook. Black is up 7 point(s) of material.


Prompt:
FEN: r3kbnr/pp2pppp/1qn5/3pP3/1p1P2b1/P4N2/2P2PPP/RNBQKB1R w KQkq -
What is on c5?

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


Prompt:
FEN: 2k4r/pb1p1r2/4p3/3pP1Bp/8/2PB4/PP3bPP/2R2R1K w - - 0 20
What is the compressed FEN row for rank 1?

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


Prompt:
FEN: 1K6/2P5/1q6/8/8/8/3k4/8 w - -
For square e6, 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>".

e6: file=e; rank=6; fen_row_from_top=3; file_index=5


Prompt:
FEN: r2qk2r/1bp1npb1/p3p1pp/1p1pP3/3P1PP1/P1QBBN2/1PP4P/2KR2R1 b kq -
Compressed rank 7 row: 1bp1npb1
Expand it into file cells a through h.

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


Prompt:
Rank 1 row before: 3q4
File d changes from q to 1. Rewrite the compressed row.

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


Prompt:
Board FEN before: r4rk1/p1pq1p1p/1pNp1npb/3Pp3/1PP3b1/P3PN2/4QP1B/2R1K1R1
Apply square edits: b4 P->1; b5 1->P
Return the resulting board FEN only.

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

Result board FEN: r4rk1/p1pq1p1p/1pNp1npb/1P1Pp3/2P3b1/P3PN2/4QP1B/2R1K1R1


Prompt:
Starting FEN: rn3rk1/p2p1pq1/1pb4p/5Q2/4P3/4b1PB/P6P/2R2RK1 w - - 0 22
Move: g1g2
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; g2=empty.
Squares: g1 white king->empty; g2 empty->white king.
Ranks: rank 1 g K->1; rank 2 g 1->K.


Prompt:
Starting FEN: r1bq1rk1/pp3p1p/2pp4/4Pp2/4P1n1/2N3P1/PPP1Q1BP/R4RK1 w - - 0 16
Move: h2h4
Use square lookups and rank edits to assemble the resulting full FEN.
State needed for full FEN:
Side to move: white
Castling rights: none
En passant: none
Halfmove clock: 0
Fullmove number: 16

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

Move 1: white pawn h2h4.
Lookup: h2=white pawn; h4=empty.
Squares: h2 white pawn->empty; h4 empty->white pawn.
Ranks: rank 2 h P->1; rank 4 h 1->P.
Result FEN: r1bq1rk1/pp3p1p/2pp4/4Pp2/4P1nP/2N3P1/PPP1Q1B1/R4RK1 b - - 0 16


Prompt:
Starting FEN: r7/5kpp/b1p3q1/p2p1r2/3P4/P1N1QP2/1P3P1P/4R2K w - - 3 27
Move: h2h4
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: 3
Fullmove number: 27

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

Rows: rank 2 1P3P1P->1P3P2; rank 4 3P4->3P3P.
Result FEN: r7/5kpp/b1p3q1/p2p1r2/3P3P/P1N1QP2/1P3P2/4R2K b - - 0 27


Prompt:
Starting FEN: r4rk1/5pp1/2nqpnbp/p2p4/3P3Q/1BP1RP2/P2N2PP/R5K1 w - - 2 23
After the moves e3d3, 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: 23

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

Result FEN: r4rk1/5pp1/2nqpnbp/p2p4/3P3Q/1BPR1P2/P2N2PP/R5K1 b - - 3 23


Prompt:
FEN: r2q1rk1/pp3ppp/5n2/1b1pP3/Q7/2B5/P4PPP/R4RK1 w - - 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=a4; rook=a1,f1; bishop=c3; knight=none; pawn=a2,f2,g2,h2,e5.
Black inventory: king=g8; queen=d8; rook=a8,f8; bishop=b5; knight=f6; pawn=d5,a7,b7,f7,g7,h7.


Prompt:
FEN: rn1qkb1r/pp2ppp1/2p2n2/3p1b1p/3P1B2/2N1PP2/PPP3PP/R2QKBNR w KQkq -
Count each piece type for both sides.

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

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


Prompt:
FEN: 8/1R4p1/2n1ppkp/2P5/3P4/r2n1P2/p2B2PP/R5K1 b - - 6 37
Convert the piece counts into material value totals.

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

White values: king=0; queen=0; rook=10; bishop=3; knight=0; pawn=5; total=18.
Black values: king=0; queen=0; rook=5; bishop=0; knight=6; pawn=5; total=16.


Prompt:
FEN: 1k6/1p3r2/1R1R1p2/3PpPp1/6P1/5PK1/2rB4/8 b - - 0 39
Trace inventory, counts, values, and material balance.

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

Inventory: white king=g3; queen=none; rook=b6,d6; bishop=d2; knight=none; pawn=f3,g4,d5,f5 | black king=b8; queen=none; rook=c2,f7; bishop=none; knight=none; pawn=e5,g5,f6,b7
Counts: white king=1; queen=0; rook=2; bishop=1; knight=0; pawn=4 | black king=1; queen=0; rook=2; bishop=0; knight=0; pawn=4
Values: white total=17; black total=14
Balance: White is up 3 point(s) of material.


Prompt:
Starting FEN: r2qkb1r/1b1n1ppp/p2pp3/8/PN1Nn3/4B3/1PP1BPPP/R2Q1RK1 w kq - 0 1
After the moves e3d2 a8c8 b2b3, what is the resulting position?
State needed for full FEN:
Side to move: white
Castling rights: kq
En passant: none
Halfmove clock: 0
Fullmove number: 1

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

Result FEN: 2rqkb1r/1b1n1ppp/p2pp3/8/PN1Nn3/1P6/2PBBPPP/R2Q1RK1 b k - 0 2


Prompt:
Position (FEN): rnb1kbnr/pppp1ppp/8/8/3pPP1q/6P1/PPP4P/RNBQKBNR b KQkq -
Show me the board.


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

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

rnbqkb1r/pp3p1p/4pnp1/3pB3/3PP3/2N5/PP3PPP/R2QKBNR b KQkq - 0 1


Prompt:
FEN: rn1qk2r/ppp2ppp/3bbn2/3p4/2PP4/3B1N2/PP2QPPP/RNB1K2R b KQkq -
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: 5rk1/1pp3pp/3q4/p3pr2/8/3nQB2/bP1NRPPP/R5K1 b - -
What is the material count for both sides?

White (10 pieces): 1 bishop, 1 king, 1 knight, 4 pawns, 1 queen, 2 rooks. Black (12 pieces): 1 bishop, 1 king, 1 knight, 6 pawns, 1 queen, 2 rooks. Black is up 2 point(s) of material.


Prompt:
FEN: r1bq1rk1/ppp1bppp/4p3/3pP3/8/P2Q1N2/1PP2PPP/RNB2RK1 w - - 3 11
What is on e3?

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


Prompt:
FEN: 2kr1b1r/ppp1pppp/2n2n2/q7/3P1Q2/2N2B2/PPP2PPP/R1B1K2R b KQ -
What is the compressed FEN row for rank 2?

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


Prompt:
FEN: rn1qkbnr/pp2pppp/2p5/5b2/2pP4/2N1P3/PP3PPP/R1BQKBNR w KQkq - 0 5
For square d2, give the FEN row-from-top and file index.

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

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


Prompt:
FEN: r2qkb1r/pp1n1ppp/2ppbn2/4p3/2P1P3/2NP1N2/PP2BPPP/R1BQ1RK1 b kq - 0 7
Compressed rank 5 row: 4p3
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: 5PK1
File g changes from K to 1. Rewrite the compressed row.

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


r2qk1nr/ppp1bppp/3pb3/4n3/4P3/2N2N2/PPP1BPPP/R1BQ1RK1 b kq - 1 8

Prompt:
Board FEN before: r2qk1nr/ppp1bppp/3pb3/4n3/4P3/2N2N2/PPP1BPPP/R1BQ1RK1
Apply square edits: g7 p->1; g5 1->p
Return the resulting board FEN only.

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

Result board FEN: r2qk1nr/ppp1bp1p/3pb3/4n1p1/4P3/2N2N2/PPP1BPPP/R1BQ1RK1


Prompt:
Starting FEN: r6r/1p1k1ppp/1Pp1p3/3p1b2/3P4/P3P3/5PPP/R3KB1R b KQ -
Move: f5g4
List the square lookups and rank edits.

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

Lookup: f5=black bishop; g4=empty.
Squares: f5 black bishop->empty; g4 empty->black bishop.
Ranks: rank 5 f b->1; rank 4 g 1->b.


Prompt:
Starting FEN: r5k1/2p2p1p/3p2p1/pPpRnn2/P7/r7/4R3/4K3 w - - 1 32
Move: d5d3
Use square lookups and rank edits to assemble the resulting full FEN.
State needed for full FEN:
Side to move: white
Castling rights: none
En passant: none
Halfmove clock: 1
Fullmove number: 32

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

Move 1: white rook d5d3.
Lookup: d5=white rook; d3=empty.
Squares: d5 white rook->empty; d3 empty->white rook.
Ranks: rank 5 d R->1; rank 3 d 1->R.
Result FEN: r5k1/2p2p1p/3p2p1/pPp1nn2/P7/r2R4/4R3/4K3 b - - 2 32


Prompt:
Starting FEN: 5rk1/3bbp2/4p1p1/p7/3P4/2N1PN2/Pr3PP1/2R1KB1R w K - 0 23
Move: f3g1
Rewrite the affected compressed FEN rank rows and give Result FEN.
State needed for full FEN:
Side to move: white
Castling rights: K
En passant: none
Halfmove clock: 0
Fullmove number: 23

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

Rows: rank 3 2N1PN2->2N1P3; rank 1 2R1KB1R->2R1KBNR.
Result FEN: 5rk1/3bbp2/4p1p1/p7/3P4/2N1P3/Pr3PP1/2R1KBNR b K - 1 23


Prompt:
Starting FEN: rnbq1rk1/pp3ppp/4pn2/2bp2B1/2P5/2N1PN2/PP3PPP/R2QKB1R b KQ - 0 1
After the moves c5b6, 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: 1

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

Result FEN: rnbq1rk1/pp3ppp/1b2pn2/3p2B1/2P5/2N1PN2/PP3PPP/R2QKB1R w KQ - 1 2


Prompt:
FEN: r1b1kb1r/p2p1pp1/4p2p/1pp1q3/3nP3/P1NP4/BPP2PPP/R2QK1NR b KQkq -
List the material inventory by side and piece type.

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

White inventory: king=e1; queen=d1; rook=a1,h1; bishop=a2; knight=g1,c3; pawn=b2,c2,f2,g2,h2,a3,d3,e4.
Black inventory: king=e8; queen=e5; rook=a8,h8; bishop=c8,f8; knight=d4; pawn=b5,c5,e6,h6,a7,d7,f7,g7.


Prompt:
FEN: r3kb1r/1ppbppp1/p1n5/5n1p/5P2/2N2N2/PPP1BBPP/3R1K1R b - -
Count each piece type for both sides.

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

White counts: king=1; queen=0; rook=2; bishop=2; knight=2; pawn=6.
Black counts: king=1; queen=0; rook=2; bishop=2; knight=2; pawn=7.


Prompt:
FEN: 8/5p2/5p2/2Nk4/1p6/7P/1P3PP1/5K2 w - - 5 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=3; pawn=4; total=7.
Black values: king=0; queen=0; rook=0; bishop=0; knight=0; pawn=3; total=3.


Prompt:
FEN: 4r3/1p3pk1/p4p1p/3N4/8/8/PPPR1PPP/2K5 w - - 6 27
Trace inventory, counts, values, and material balance.

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

Inventory: white king=c1; queen=none; rook=d2; bishop=none; knight=d5; pawn=a2,b2,c2,f2,g2,h2 | black king=g7; queen=none; rook=e8; bishop=none; knight=none; pawn=a6,f6,h6,b7,f7
Counts: white king=1; queen=0; rook=1; bishop=0; knight=1; pawn=6 | black king=1; queen=0; rook=1; bishop=0; knight=0; pawn=5
Values: white total=14; black total=10
Balance: White is up 4 point(s) of material.


Prompt:
Starting FEN: 8/8/3k1Pp1/8/8/8/2K5/8 w - - 0 1
After the moves c2b3 d6c6 b3a4, 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): 8/8/3bb3/6K1/5r2/8/2k5/8 b - -
Show me the board.


Prompt:
Here is the current board:
8 r n b q . r k .
7 p p p p b p p p
6 . . . . p . . .
5 . . . . . . . .
4 . . . P . P . .
3 P . N . . . P .
2 . P P . N P . P
1 R . . Q 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: KQ
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/ppppbppp/4p3/8/3P1P2/P1N3P1/1PP1NP1P/R2QKB1R b KQ - 0 1


Prompt:
FEN: 8/7r/8/8/6k1/2n3P1/8/q3K3 w - - 2 57
What piece is on g4?

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


Prompt:
FEN: 8/6pk/p1Q1p3/3pp2p/5n2/2P1n1qP/PP4P1/6RK w - - 0 32
What is the material count for both sides?

White (8 pieces): 1 king, 5 pawns, 1 queen, 1 rook. Black (10 pieces): 1 king, 2 knights, 6 pawns, 1 queen. Black is up 2 point(s) of material.


Prompt:
FEN: rn1qkb1r/ppp2ppp/4pn2/3p1b2/1P6/P3P3/1BPP1PPP/RN1QKBNR w KQkq - 2 5
What is on b6?

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


Prompt:
FEN: rn1qkb1r/pp3ppp/2pp1n2/4p3/3PP1b1/2PB1N2/PP3PPP/RNBQK2R w KQkq -
What is the compressed FEN row for rank 5?

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


Prompt:
FEN: r1bqk2r/pppn1p2/3p2p1/3Pp1NB/2P1P2p/2N4P/PP1Q1PP1/R3K2R b KQq -
For square d4, give the FEN row-from-top and file index.

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

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


Prompt:
FEN: 8/5pk1/5Np1/8/5n2/r4P1p/2Q2P1K/8 w - - 3 49
Compressed rank 8 row: 8
Expand it into file cells a through h.

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


r3k2r/ppp2ppp/3p4/2bPp3/N1P1P3/3B1n1P/PP2NqQK/R1B5 w kq -

Prompt:
Rank 1 row before: R1B5
File h changes from 1 to K. Rewrite the compressed row.

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


Prompt:
Board FEN before: 8/8/8/1P6/2k5/8/8/7K
Apply square edits: c4 k->1; c5 1->k
Return the resulting board FEN only.

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


Prompt:
Starting FEN: r6r/pppkq1p1/3pp2p/7Q/3pP2P/2P3P1/PP1R1P2/2K4R w - - 0 20
Move: c3d4
List the square lookups and rank edits.

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

Lookup: c3=white pawn; d4=black pawn.
Squares: c3 white pawn->empty; d4 black pawn->white pawn.
Ranks: rank 3 c P->1; rank 4 d p->P.


Prompt:
Starting FEN: 4r3/5pk1/6p1/4p3/4Q1Pq/rP2R3/P4PK1/R7 b - - 0 1
Move: e8c8
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 e8c8.
Lookup: e8=black rook; c8=empty.
Squares: e8 black rook->empty; c8 empty->black rook.
Ranks: rank 8 e r->1; rank 8 c 1->r.
Result FEN: 2r5/5pk1/6p1/4p3/4Q1Pq/rP2R3/P4PK1/R7 w - - 1 2


Prompt:
Starting FEN: 6k1/4q1p1/p3p2p/P1rpPp1b/1P1n4/8/3Q1PPP/R4BK1 w - - 0 1
Move: d2b2
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 2 3Q1PPP->1Q3PPP.
Result FEN: 6k1/4q1p1/p3p2p/P1rpPp1b/1P1n4/8/1Q3PPP/R4BK1 b - - 1 1


Prompt:
Starting FEN: r4rk1/pppb1pp1/2n1pq1p/8/Q1pP4/2P1PN2/P3BPPP/R4RK1 w - - 0 1
After the moves a1d1, what is the resulting position?
State needed for full FEN:
Side to move: white
Castling rights: none
En passant: none
Halfmove clock: 0
Fullmove number: 1

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

Result FEN: r4rk1/pppb1pp1/2n1pq1p/8/Q1pP4/2P1PN2/P3BPPP/3R1RK1 b - - 1 1


Prompt:
FEN: 8/8/5R2/1r4p1/1P2k3/P4P2/2K4P/8 b - - 0 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=c2; queen=none; rook=f6; bishop=none; knight=none; pawn=h2,a3,f3,b4.
Black inventory: king=e4; queen=none; rook=b5; bishop=none; knight=none; pawn=g5.


Prompt:
FEN: r1b1k1nr/ppp2p1p/2np1qp1/2b1p1Q1/2B1P3/2N2N2/PPPP1PPP/R1B2RK1 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=2; pawn=8.
Black counts: king=1; queen=1; rook=2; bishop=2; knight=2; pawn=8.


Prompt:
FEN: rnbqr1k1/bp3ppp/p4n2/P2pN3/1P3P2/2PB4/6PP/RNBQK2R w KQ - 1 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=6; knight=6; pawn=6; total=37.
Black values: king=0; queen=9; rook=10; bishop=6; knight=6; pawn=6; total=37.


Prompt:
FEN: 8/8/2k5/8/8/B7/8/4KN2 w - -
Trace inventory, counts, values, and material balance.

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

Inventory: white king=e1; queen=none; rook=none; bishop=a3; knight=f1; pawn=none | black king=c6; 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: r1b2r1k/1p5p/p1p2qpQ/2P2p2/PPB1p3/1N5P/5PP1/R4RK1 b - - 1 20
After the moves f8d8 f1e1 d8g8, 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: 20

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

Result FEN: r1b3rk/1p5p/p1p2qpQ/2P2p2/PPB1p3/1N5P/5PP1/R3R1K1 w - - 4 22


Prompt:
Position (FEN): r4r2/1p1n2k1/pqb1p1pR/3p4/1P1P2P1/2P2P1N/P2QP3/R3KB2 b Q - 1 18
Show me the board.


r1b1R1nr/ppp2pkp/3p2q1/nB4N1/8/2P3Q1/P4PPP/RN4K1 b - -

Prompt:
Here is the current board:
8 r . b . R . n r
7 p p p . . p k p
6 . . . p . . q .
5 n B . . . . N .
4 . . . . . . . .
3 . . P . . . Q .
2 P . . . . P P P
1 R N . . . . 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: r1bk3r/p1p2ppp/2p2n2/4p3/1b2P3/2N2N2/PPP2PPP/R1B1K2R w KQ - 0 9
What piece is on g2?

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: r5nr/p2k4/2ppbp2/4p1p1/2P5/4P1p1/PP3PPP/3RK1NR w K - 0 16
What is the material count for both sides?

White (11 pieces): 1 king, 1 knight, 7 pawns, 2 rooks. Black (12 pieces): 1 bishop, 1 king, 1 knight, 7 pawns, 2 rooks. Black is up 3 point(s) of material.


Prompt:
FEN: rnb2rk1/pp1p1ppp/2pq4/2b1p1B1/2B1P3/3P1N2/PPP2PPP/R2Q1RK1 w - - 2 10
What is on c7?

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


Prompt:
FEN: r5k1/1rq1bppp/3ppn2/2p5/bnP1P3/1B2BNNP/P2Q1PP1/R2R2K1 w - -
What is the compressed FEN row for rank 6?

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


Prompt:
FEN: 7k/7p/2p1pP2/2Pp1p2/3P4/8/P6P/7K b - -
For square f7, 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>".

f7: file=f; rank=7; fen_row_from_top=2; file_index=6


Prompt:
FEN: 2rq1rk1/1b1p1pp1/4pn1p/8/1b6/1N1QPN2/1P2BPPP/R1R3K1 b - - 1 17
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>".


r1b1k1nr/1p1p1ppp/pqn1p3/8/1bP2B2/PP2P3/3N1PPP/R2QKBNR b KQkq - 0 8

Prompt:
Rank 5 row before: 8
File h changes from 1 to p. Rewrite the compressed row.

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


rnbqk2r/pp3ppp/4pn2/3p4/1bPP4/2N5/PPQ2PPP/R1B1KBNR w KQkq -

Prompt:
Board FEN before: rnbqk2r/pp3ppp/4pn2/3p4/1bPP4/2N5/PPQ2PPP/R1B1KBNR
Apply square edits: c1 B->1; d2 1->B
Return the resulting board FEN only.

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

Result board FEN: rnbqk2r/pp3ppp/4pn2/3p4/1bPP4/2N5/PPQB1PPP/R3KBNR


Prompt:
Starting FEN: 8/5p2/6k1/3rp2p/7P/6P1/4R1K1/8 w - -
Move: g2f2
List the square lookups and rank edits.

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

Lookup: g2=white king; f2=empty.
Squares: g2 white king->empty; f2 empty->white king.
Ranks: rank 2 g K->1; rank 2 f 1->K.


Prompt:
Starting FEN: 5N1k/8/6K1/8/6p1/6N1/8/8 b - - 0 1
Move: h8g8
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 h8g8.
Lookup: h8=black king; g8=empty.
Squares: h8 black king->empty; g8 empty->black king.
Ranks: rank 8 h k->1; rank 8 g 1->k.
Result FEN: 5Nk1/8/6K1/8/6p1/6N1/8/8 w - - 1 2


Prompt:
Starting FEN: r1b1k2r/ppppqppp/8/4n3/1bP2B2/4P3/PP1N1PPP/R2QKB1R w KQkq - 0 1
Move: d1c1
Rewrite the affected compressed FEN rank rows and give Result FEN.
State needed for full FEN:
Side to move: white
Castling rights: KQkq
En passant: none
Halfmove clock: 0
Fullmove number: 1

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

Rows: rank 1 R2QKB1R->R1Q1KB1R.
Result FEN: r1b1k2r/ppppqppp/8/4n3/1bP2B2/4P3/PP1N1PPP/R1Q1KB1R b KQkq - 1 1


Prompt:
Starting FEN: rnbq1rk1/ppppbppp/4pn2/8/8/1P4P1/PBPPPPBP/RN1QK1NR w KQ - 3 5
After the moves b3b4, what is the resulting position?
State needed for full FEN:
Side to move: white
Castling rights: KQ
En passant: none
Halfmove clock: 3
Fullmove number: 5

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

Result FEN: rnbq1rk1/ppppbppp/4pn2/8/1P6/6P1/PBPPPPBP/RN1QK1NR b KQ - 0 5


Prompt:
FEN: 2rq1rk1/pb1n1ppp/1p1b1n2/2pp4/3P4/1P3NP1/PBQNPPBP/2R2RK1 w - -
List the material inventory by side and piece type.

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

White inventory: king=g1; queen=c2; rook=c1,f1; bishop=b2,g2; knight=d2,f3; pawn=a2,e2,f2,h2,b3,g3,d4.
Black inventory: king=g8; queen=d8; rook=c8,f8; bishop=d6,b7; knight=f6,d7; pawn=c5,d5,b6,a7,f7,g7,h7.


Prompt:
FEN: rnb1k1nr/1p3ppp/p1p1p3/q2P4/PbB1P3/2N5/1P3PPP/R1BQK1NR w KQkq - 1 8
Count each piece type for both sides.

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

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


Prompt:
FEN: r2qkbnr/pp3ppp/2n1p3/2pp1b2/2PP4/2N1PN2/PP2BPPP/R1BQK2R b KQkq -
Convert the piece counts into material value totals.

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

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


Prompt:
FEN: r5k1/pp2pr1p/2pbN1p1/2n2pP1/7P/2N5/PP4B1/2KR3R w - - 6 20
Trace inventory, counts, values, and material balance.

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

Inventory: white king=c1; queen=none; rook=d1,h1; bishop=g2; knight=c3,e6; pawn=a2,b2,h4,g5 | black king=g8; queen=none; rook=f7,a8; bishop=d6; knight=c5; pawn=f5,c6,g6,a7,b7,e7,h7
Counts: white king=1; queen=0; rook=2; bishop=1; knight=2; pawn=4 | black king=1; queen=0; rook=2; bishop=1; knight=1; pawn=7
Values: white total=23; black total=23
Balance: Material is equal.


Prompt:
Starting FEN: rn2k2r/ppqb1ppp/2p1pn2/3p4/P2P4/1PBBPP2/2P1N1PP/R2Q1RK1 w kq - 1 12
After the moves d3b5 e8g8, what is the resulting position?
State needed for full FEN:
Side to move: white
Castling rights: kq
En passant: none
Halfmove clock: 1
Fullmove number: 12

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

Result FEN: rn3rk1/ppqb1ppp/2p1pn2/1B1p4/P2P4/1PB1PP2/2P1N1PP/R2Q1RK1 w - - 3 13


Prompt:
Position (FEN): 4k2r/1pp3p1/4bp2/4p3/pb6/5R1P/P2r2P1/2K5 b k - 3 32
Show me the board.


rnbqkb1r/pp3ppp/3ppn2/8/2BNP3/8/PPP2PPP/RNBQK2R w KQkq - 1 6

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

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


Prompt:
FEN: r4rk1/p4pp1/3p2q1/2p5/5P2/6Q1/PP4RP/R6K w - - 4 27
What piece is on a8?

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: r1b2rk1/ppq1ppbp/3p1np1/4n3/P1B1P3/1NN1BP2/1PP3PP/R2Q1RK1 w - -
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: r4rk1/pp1n1pp1/2pb1q1p/3p4/3P4/2N2bPP/PPP2PB1/R2QR1K1 w - - 0 13
What is on b5?

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


Prompt:
FEN: r3k2r/ppqbbpp1/2n1pn2/3pN2p/PPpP1P2/2P1P3/2BN2PP/R1BQ1RK1 w kq - 1 13
What is the compressed FEN row for rank 7?

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


Prompt:
FEN: 3Rkb1r/pp2pppp/1n6/4P3/8/5N2/PP4PP/R1B3K1 b k - 0 16
For square c1, 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>".

c1: file=c; rank=1; fen_row_from_top=8; file_index=3


Prompt:
FEN: 8/4k3/B7/5K2/3Q4/8/8/8 w - -
Compressed rank 1 row: 8
Expand it into file cells a through h.

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


Prompt:
Rank 1 row before: 2R5
File g changes from 1 to R. Rewrite the compressed row.

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


r1b2rk1/2q1bppp/p1p5/2Ppn3/Q7/1NP1B2P/PP2B1P1/R4R1K b - -

Prompt:
Board FEN before: r1b2rk1/2q1bppp/p1p5/2Ppn3/Q7/1NP1B2P/PP2B1P1/R4R1K
Apply square edits: c8 b->1; g4 1->b
Return the resulting board FEN only.

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

Result board FEN: r4rk1/2q1bppp/p1p5/2Ppn3/Q5b1/1NP1B2P/PP2B1P1/R4R1K


Prompt:
Starting FEN: r1b4r/1p2knpp/p2npp2/2B5/8/2N5/PP3PPP/R3KB1R w KQ -
Move: c5a3
List the square lookups and rank edits.

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

Lookup: c5=white bishop; a3=empty.
Squares: c5 white bishop->empty; a3 empty->white bishop.
Ranks: rank 5 c B->1; rank 3 a 1->B.


Prompt:
Starting FEN: 2krr3/pbppn1b1/1p6/6pp/3NP3/2QBBnP1/PPP4P/2KR3R w - - 4 18
Move: d3e2
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: 4
Fullmove number: 18

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

Move 1: white bishop d3e2.
Lookup: d3=white bishop; e2=empty.
Squares: d3 white bishop->empty; e2 empty->white bishop.
Ranks: rank 3 d B->1; rank 2 e 1->B.
Result FEN: 2krr3/pbppn1b1/1p6/6pp/3NP3/2Q1BnP1/PPP1B2P/2KR3R b - - 5 18


Prompt:
Starting FEN: 2r3k1/pq2nR1B/4p2b/1pPbN1p1/3P2P1/8/P7/4R1K1 b - - 0 1
Move: g8h8
Rewrite the affected compressed FEN rank rows and give Result FEN.
State needed for full FEN:
Side to move: black
Castling rights: none
En passant: none
Halfmove clock: 0
Fullmove number: 1

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

Rows: rank 8 2r3k1->2r4k.
Result FEN: 2r4k/pq2nR1B/4p2b/1pPbN1p1/3P2P1/8/P7/4R1K1 w - - 1 2


Prompt:
Starting FEN: r2r2k1/6pp/1n2qp2/p1R3Q1/1p1Pp3/1P2B2P/P4PP1/1R4K1 w - - 0 26
After the moves g1f1, 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: 26

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


Prompt:
FEN: rnb2r2/1ppp2kp/2n3p1/p2p1p2/P1P5/2N1PN2/2K1BPPP/7R w - - 0 19
List the material inventory by side and piece type.

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

White inventory: king=c2; queen=none; rook=h1; bishop=e2; knight=c3,f3; pawn=f2,g2,h2,e3,a4,c4.
Black inventory: king=g7; queen=none; rook=a8,f8; bishop=c8; knight=c6,b8; pawn=a5,d5,f5,g6,b7,c7,d7,h7.


Prompt:
FEN: 8/5ppk/q6p/1p1Np3/2p1P3/1nP4P/1Q3PP1/5K2 w - - 9 42
Count each piece type for both sides.

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

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


Prompt:
FEN: r1bqkbnr/pp2pppp/2n5/2p5/4Q3/P1P4P/1P1P1PP1/RNB1KBNR b KQkq - 0 6
Convert the piece counts into material value totals.

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

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


Prompt:
FEN: rnbqkbnr/pp3ppp/4p3/1B1p4/8/5N2/PPPP1PPP/RNBQK2R b KQkq - 1 5
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,b5; knight=b1,f3; pawn=a2,b2,c2,d2,f2,g2,h2 | black king=e8; queen=d8; rook=a8,h8; bishop=c8,f8; knight=b8,g8; pawn=d5,e6,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: r3kb1r/pppqnppp/2b1p3/3pP1N1/3P4/8/PPP2PPP/RNBQ1RK1 b kq - 3 8
After the moves f7f5 a2a3 f5f4, what is the resulting position?
State needed for full FEN:
Side to move: black
Castling rights: kq
En passant: none
Halfmove clock: 3
Fullmove number: 8

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

Result FEN: r3kb1r/pppqn1pp/2b1p3/3pP1N1/3P1p2/P7/1PP2PPP/RNBQ1RK1 w kq - 0 10


Prompt:
Position (FEN): 5qr1/p1p3bk/1p2pr1p/3p1pQR/1P1P1P2/P3P2R/2P1N1PP/6K1 w - - 8 31
Show me the board.


Prompt:
Here is the current board:
8 . . . . . . k .
7 . . . . . . p .
6 . . p . . p . .
5 . . . b p . p .
4 . . . . . . . .
3 . R . N . . P K
2 . P . . . P . P
1 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: none
En passant: none
Halfmove clock: 3
Fullmove number: 34

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


Prompt:
FEN: 8/4b1n1/3p1pkp/2rPp1p1/4P3/5PPP/R1PN1K2/4R3 b - - 0 39
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: r3k1r1/ppp1bppp/5qb1/3P4/2n3P1/2N5/PPP1Q2P/2KR3R b q - 3 15
What is the material count for both sides?

White (11 pieces): 1 king, 1 knight, 6 pawns, 1 queen, 2 rooks. Black (13 pieces): 2 bishops, 1 king, 1 knight, 6 pawns, 1 queen, 2 rooks. Black is up 6 point(s) of material.


Prompt:
FEN: 2r4r/1b3kpp/8/pP6/Pb6/2N1pP1P/6P1/2R1K1NR w K - 0 22
What is on d8?

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


Prompt:
FEN: rnb1kbnr/pp3ppp/3q4/2p5/2Pp4/5N2/PPQNPPPP/R1B1KB1R w KQkq - 0 9
What is the compressed FEN row for rank 2?

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


Prompt:
FEN: 8/2K1k3/2P5/8/8/8/2r5/4R3 b - -
For square b6, 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>".

b6: file=b; rank=6; fen_row_from_top=3; file_index=2


Prompt:
FEN: rn1qkb1r/p1pp1ppp/1p2p3/8/2BP2n1/4Q2N/PPP2PbP/RNB1K1R1 w Qkq - 2 8
Compressed rank 7 row: p1pp1ppp
Expand it into file cells a through h.

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


Prompt:
Rank 8 row before: r5k1
File a changes from r to 1. Rewrite the compressed row.

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


Prompt:
Board FEN before: 7k/8/3p2p1/1p1Q1q2/5PpP/2P3K1/1P1R4/r7
Apply square edits: a1 r->1; a2 1->r
Return the resulting board FEN only.

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

Result board FEN: 7k/8/3p2p1/1p1Q1q2/5PpP/2P3K1/rP1R4/8


Prompt:
Starting FEN: 5rk1/ppQ4p/4pqp1/8/3P4/P1P5/1P3PPP/4R1K1 w - -
Move: c7c5
List the square lookups and rank edits.

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

Lookup: c7=white queen; c5=empty.
Squares: c7 white queen->empty; c5 empty->white queen.
Ranks: rank 7 c Q->1; rank 5 c 1->Q.


Prompt:
Starting FEN: r2q1rk1/1p3pp1/p2bpnnp/3p2B1/3N1P2/8/PPP1Q1PP/RN3RK1 w - - 0 15
Move: f1e1
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: 15

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

Move 1: white rook f1e1.
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.
Result FEN: r2q1rk1/1p3pp1/p2bpnnp/3p2B1/3N1P2/8/PPP1Q1PP/RN2R1K1 b - - 1 15


Prompt:
Starting FEN: rn1qkbnr/2pppppp/b7/8/8/5N2/PP1PPPPP/RNBQKB1R b KQkq - 0 1
Move: e7e6
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 7 2pppppp->2pp1ppp; rank 6 b7->b3p3.
Result FEN: rn1qkbnr/2pp1ppp/b3p3/8/8/5N2/PP1PPPPP/RNBQKB1R w KQkq - 0 2


Prompt:
Starting FEN: 8/p1p5/2p3pr/1pPk1p2/3P1P2/4P1N1/PP3PK1/8 w - - 1 32
After the moves b2b4, what is the resulting position?
State needed for full FEN:
Side to move: white
Castling rights: none
En passant: none
Halfmove clock: 1
Fullmove number: 32

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


Prompt:
FEN: r1bqkb1r/p2n1ppp/2p1pn2/4P3/1ppP4/2N2NP1/PP3PBP/R1BQ1RK1 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=g1; queen=d1; rook=a1,f1; bishop=c1,g2; knight=c3,f3; pawn=a2,b2,f2,h2,g3,d4,e5.
Black inventory: king=e8; queen=d8; rook=a8,h8; bishop=c8,f8; knight=f6,d7; pawn=b4,c4,c6,e6,a7,f7,g7,h7.


Prompt:
FEN: 1k1r1b1r/ppp1qpp1/8/1P6/Q2p4/P2P1BP1/4P2P/R4RK1 b - - 0 20
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=1; rook=2; bishop=1; knight=0; pawn=6.


Prompt:
FEN: 4r3/1pR5/p1b3k1/8/PP4p1/2N5/6P1/6K1 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=3; total=11.
Black values: king=0; queen=0; rook=5; bishop=3; knight=0; pawn=3; total=11.


Prompt:
FEN: 5Q2/8/8/1p4Q1/pP6/K7/6k1/8 b - - 3 67
Trace inventory, counts, values, and material balance.

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

Inventory: white king=a3; queen=g5,f8; rook=none; bishop=none; knight=none; pawn=b4 | black king=g2; queen=none; rook=none; bishop=none; knight=none; pawn=a4,b5
Counts: white king=1; queen=2; rook=0; bishop=0; knight=0; pawn=1 | black king=1; queen=0; rook=0; bishop=0; knight=0; pawn=2
Values: white total=19; black total=2
Balance: White is up 17 point(s) of material.


Prompt:
Starting FEN: r1bq1rk1/1p2npp1/p1np3p/5P2/3P3N/2P5/P3B1PP/R1BQ1RK1 b - - 0 13
After the moves d8e8 c1f4 c6d4, 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: 13

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

Result FEN: r1b1qrk1/1p2npp1/p2p3p/5P2/3n1B1N/2P5/P3B1PP/R2Q1RK1 w - - 0 15


Prompt:
Position (FEN): 6q1/pp1kn2p/4pQ2/1NppPp2/3P4/2P5/PP1R2PP/6K1 w - - 4 27
Show me the board.


Prompt:
Here is the current board:
8 r . . . . r . .
7 p p p . . p . k
6 . . n . b . p .
5 . . . p p q . .
4 . . . . N . . .
3 . . P Q B . . P
2 P . 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: 0
Fullmove number: 17

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


Prompt:
FEN: 6rk/pp1q1p2/2r5/3p1p2/3P1P2/1P1QP1P1/P6P/2R2RK1 b - - 2 25
What piece is on d5?

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


Prompt:
FEN: r5R1/2Q1k3/p2p4/4p3/8/2PqB2p/PP3P2/4K3 b - - 0 34
What is the material count for both sides?

White (8 pieces): 1 bishop, 1 king, 4 pawns, 1 queen, 1 rook. Black (7 pieces): 1 king, 4 pawns, 1 queen, 1 rook. White is up 3 point(s) of material.


Prompt:
FEN: rnbqk2r/p3ppbp/2pp2p1/7P/1p1Pn3/1B3N2/PPP1NPP1/R1BQK2R b KQkq - 1 9
What is on e2?

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


Prompt:
FEN: rnbqkbnr/pp3ppp/4p3/3p4/3Q1B2/2N3P1/PPP1PP1P/R3KBNR b KQkq - 0 5
What is the compressed FEN row for rank 4?

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


Prompt:
FEN: 2k5/p5r1/4n3/2pR4/P7/1PPK4/3N4/8 w - - 1 36
For square h8, 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>".

h8: file=h; rank=8; fen_row_from_top=1; file_index=8


Prompt:
FEN: 8/3bq1pk/Q1p1p2p/3nPp2/3P4/P4N2/2B2PPP/r1B2RK1 w - - 5 30
Compressed rank 8 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: 2k5
File c changes from k to 1. Rewrite the compressed row.

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


Prompt:
Board FEN before: 2r1r1k1/1p4pp/2p2p2/3n4/p2P4/P4NP1/1PR2P1P/4RK2
Apply square edits: d5 n->1; b4 1->n
Return the resulting board FEN only.

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

Result board FEN: 2r1r1k1/1p4pp/2p2p2/8/pn1P4/P4NP1/1PR2P1P/4RK2


Prompt:
Starting FEN: r4k2/1p1b4/p2p2Q1/2pPq1P1/P3N2p/8/1P3N1P/5BK1 w - -
Move: g6e8
List the square lookups and rank edits.

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

Lookup: g6=white queen; e8=empty.
Squares: g6 white queen->empty; e8 empty->white queen.
Ranks: rank 6 g Q->1; rank 8 e 1->Q.