Prompt:
Position (FEN): rnb2rk1/ppqpppbp/5np1/8/8/2PBPN2/PP1N1PPP/R1BQ1RK1 b - - 7 9
Show me the board.


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

r1b2rk1/pp1n1pp1/2n1pb1p/q2p4/3P4/2N1PNB1/PPB2PPP/R2QK2R w KQ - 0 1


Prompt:
FEN: 1rbq1r1k/3n2pp/p1B2b2/2p5/1p3P2/3P2PP/PPPBN2K/1R1QR3 b - -
What piece is on b8?

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: 8/5kpp/8/p3KPP1/P7/8/8/8 b - - 0 50
What is the material count for both sides?

White (4 pieces): 1 king, 3 pawns. Black (4 pieces): 1 king, 3 pawns. Material is equal.


Prompt:
FEN: r1b1r3/pp1k3p/3p2p1/5n2/2Bn4/2Q5/PPP2PPP/RN4K1 w - - 3 19
What is on d4?

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


Prompt:
FEN: 8/8/8/5BK1/1k6/1N6/8/8 w - -
What is the compressed FEN row for rank 6?

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


Prompt:
FEN: r2q1rk1/1pp2p1b/p2p2p1/4p1n1/4P3/2PPB1N1/PPB1QP2/2K4R w - - 0 23
For square a2, give the FEN row-from-top and file index.

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

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


Prompt:
FEN: 8/8/8/1P5p/5K2/1k5P/8/2r5 b - -
Compressed rank 3 row: 1k5P
Expand it into file cells a through h.

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


Prompt:
Rank 5 row before: 2p5
File g changes from 1 to p. Rewrite the compressed row.

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


r2qk2r/ppp2ppp/2nbbn2/8/4pP2/1P2P1P1/PBP3BP/RN1QK1NR w KQkq - 0 9

Prompt:
Board FEN before: r2qk2r/ppp2ppp/2nbbn2/8/4pP2/1P2P1P1/PBP3BP/RN1QK1NR
Apply square edits: d1 Q->1; d2 1->Q
Return the resulting board FEN only.

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

Result board FEN: r2qk2r/ppp2ppp/2nbbn2/8/4pP2/1P2P1P1/PBPQ2BP/RN2K1NR


Prompt:
Starting FEN: R7/5p1k/5p1p/5P2/6KP/6P1/p7/r7 b - - 0 34
Move: a1d1
List the square lookups and rank edits.

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

Lookup: a1=black rook; d1=empty.
Squares: a1 black rook->empty; d1 empty->black rook.
Ranks: rank 1 a r->1; rank 1 d 1->r.


Prompt:
Starting FEN: r2q1rk1/pbp2ppp/8/1p6/3b4/1B1P2QP/PPP2nPK/RNB1R3 b - - 0 1
Move: c7c5
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 pawn c7c5.
Lookup: c7=black pawn; c5=empty.
Squares: c7 black pawn->empty; c5 empty->black pawn.
Ranks: rank 7 c p->1; rank 5 c 1->p.
Result FEN: r2q1rk1/pb3ppp/8/1pp5/3b4/1B1P2QP/PPP2nPK/RNB1R3 w - - 0 2


Prompt:
Starting FEN: 4rrk1/ppBbqn1p/2n2b1P/1N1p2p1/3p4/5NP1/PP2BP2/R2QR1K1 w - - 0 1
Move: f3d2
Rewrite the affected compressed FEN rank rows and give Result FEN.
State needed for full FEN:
Side to move: white
Castling rights: none
En passant: none
Halfmove clock: 0
Fullmove number: 1

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

Rows: rank 3 5NP1->6P1; rank 2 PP2BP2->PP1NBP2.
Result FEN: 4rrk1/ppBbqn1p/2n2b1P/1N1p2p1/3p4/6P1/PP1NBP2/R2QR1K1 b - - 1 1


Prompt:
Starting FEN: 8/8/4k3/6R1/8/8/5R2/2K5 w - - 0 1
After the moves g5c5, what is the resulting position?
State needed for full FEN:
Side to move: white
Castling rights: none
En passant: none
Halfmove clock: 0
Fullmove number: 1

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


Prompt:
FEN: 2kr2nr/pbppq1b1/np3p2/4p1pp/2P5/P1NPPNPP/1P3PB1/R1BQ1RK1 w - - 3 11
List the material inventory by side and piece type.

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

White inventory: king=g1; queen=d1; rook=a1,f1; bishop=c1,g2; knight=c3,f3; pawn=b2,f2,a3,d3,e3,g3,h3,c4.
Black inventory: king=c8; queen=e7; rook=d8,h8; bishop=b7,g7; knight=a6,g8; pawn=e5,g5,h5,b6,f6,a7,c7,d7.


Prompt:
FEN: r4rk1/p2n2p1/2p1p2p/qp2p3/3pP3/P2P1N1P/1PP1QPP1/2K2R1R w - - 4 17
Count each piece type for both sides.

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

White counts: king=1; queen=1; rook=2; bishop=0; knight=1; pawn=8.
Black counts: king=1; queen=1; rook=2; bishop=0; knight=1; pawn=8.


Prompt:
FEN: 7k/8/5K2/8/7N/1B6/8/8 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=0; bishop=3; knight=3; pawn=0; total=6.
Black values: king=0; queen=0; rook=0; bishop=0; knight=0; pawn=0; total=0.


Prompt:
FEN: 7r/2p2p2/3k3p/3p1bp1/1Q6/3P1P2/1PP2P1P/5RK1 b - - 0 25
Trace inventory, counts, values, and material balance.

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

Inventory: white king=g1; queen=b4; rook=f1; bishop=none; knight=none; pawn=b2,c2,f2,h2,d3,f3 | black king=d6; queen=none; rook=h8; bishop=f5; knight=none; pawn=d5,g5,h6,c7,f7
Counts: white king=1; queen=1; rook=1; bishop=0; knight=0; pawn=6 | black king=1; queen=0; rook=1; bishop=1; knight=0; pawn=5
Values: white total=20; black total=13
Balance: White is up 7 point(s) of material.


Prompt:
Starting FEN: r3k1nr/1p1bb1pp/1qn1p3/p2pPpN1/3N4/2PB4/PP3PPP/R1BQR1K1 b kq - 1 13
After the moves e7f6 d1a4, what is the resulting position?
State needed for full FEN:
Side to move: black
Castling rights: kq
En passant: none
Halfmove clock: 1
Fullmove number: 13

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

Result FEN: r3k1nr/1p1b2pp/1qn1pb2/p2pPpN1/Q2N4/2PB4/PP3PPP/R1B1R1K1 b kq - 3 14


Prompt:
Position (FEN): 1k1r3r/p1p2ppp/8/4b3/4P1q1/Q7/PPP1KP2/RNB2R2 w - - 5 21
Show me the board.


Prompt:
Here is the current board:
8 . . . . . . k .
7 . . . . . p p .
6 . . . . p . . p
5 . . . . N n . .
4 . . . . . . . .
3 R . . . P . . P
2 . . . . r . P .
1 . . . . . . K .
  a b c d e f g h
Write the FEN for this position.
State needed for full FEN:
Side to move: white
Castling rights: none
En passant: none
Halfmove clock: 5
Fullmove number: 31

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


Prompt:
FEN: 5r2/8/5p2/pR1B2pp/8/P1P5/KP3kPP/8 w - - 2 41
What piece is on b5?

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: r2r2k1/1pq1bpp1/2p1p2p/2n1P2P/p1P2P2/4B1N1/PP2Q1P1/1K1RR3 w - -
What is the material count for both sides?

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


Prompt:
FEN: 2r4k/4b1pp/8/3B4/P1p1P3/4BP2/4K1PP/2R5 b - - 1 28
What is on e4?

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


Prompt:
FEN: r4rk1/1pp3bp/3qP3/2p2p2/P1P1pn2/2N3P1/4BP1P/1RQ2RK1 b - -
What is the compressed FEN row for rank 2?

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


Prompt:
FEN: r2qk2r/pppbnpp1/3bpn1p/3p4/3P1P2/2PBPN2/PP1N2PP/R1BQ1RK1 w kq - 3 9
For square d5, give the FEN row-from-top and file index.

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

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


Prompt:
FEN: r2q2k1/pp4pp/n1r1bp2/2PBp3/8/P3Q3/2P2PPP/3RR1K1 b - - 0 21
Compressed rank 8 row: r2q2k1
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: 2kr2nq
File f changes from 1 to n. Rewrite the compressed row.

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


r3k2r/p1ppq1bp/b1p2pp1/3nP3/2P2P2/1P4P1/P3Q2P/RNB1KB1R w KQkq -

Prompt:
Board FEN before: r3k2r/p1ppq1bp/b1p2pp1/3nP3/2P2P2/1P4P1/P3Q2P/RNB1KB1R
Apply square edits: b3 P->1; b4 1->P
Return the resulting board FEN only.

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

Result board FEN: r3k2r/p1ppq1bp/b1p2pp1/3nP3/1PP2P2/6P1/P3Q2P/RNB1KB1R


Prompt:
Starting FEN: 6k1/1p4b1/1p5p/4p3/4P1B1/1PNR4/P1K5/5r2 b - -
Move: g7f6
List the square lookups and rank edits.

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

Lookup: g7=black bishop; f6=empty.
Squares: g7 black bishop->empty; f6 empty->black bishop.
Ranks: rank 7 g b->1; rank 6 f 1->b.


Prompt:
Starting FEN: 2r4k/2p4p/p4P2/1p4p1/2n2p1B/2P4P/qPQ2PP1/3R2K1 b - - 0 31
Move: c8e8
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: 31

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

Move 1: black rook c8e8.
Lookup: c8=black rook; e8=empty.
Squares: c8 black rook->empty; e8 empty->black rook.
Ranks: rank 8 c r->1; rank 8 e 1->r.
Result FEN: 4r2k/2p4p/p4P2/1p4p1/2n2p1B/2P4P/qPQ2PP1/3R2K1 w - - 1 32


Prompt:
Starting FEN: r2qkbnr/pp3ppp/2n1p3/3p4/3P1Bb1/4PN2/PP1N1PPP/R2QKB1R b KQkq - 0 1
Move: e8e7
Rewrite the affected compressed FEN rank rows and give Result FEN.
State needed for full FEN:
Side to move: black
Castling rights: KQkq
En passant: none
Halfmove clock: 0
Fullmove number: 1

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

Rows: rank 8 r2qkbnr->r2q1bnr; rank 7 pp3ppp->pp2kppp.
Result FEN: r2q1bnr/pp2kppp/2n1p3/3p4/3P1Bb1/4PN2/PP1N1PPP/R2QKB1R w KQ - 1 2


Prompt:
Starting FEN: r3k2r/1ppbqp2/1pnp1n2/4p1B1/4P1pp/2PP4/PP2BPPP/R1Q1NRK1 b kq - 1 14
After the moves c6b8, what is the resulting position?
State needed for full FEN:
Side to move: black
Castling rights: kq
En passant: none
Halfmove clock: 1
Fullmove number: 14

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

Result FEN: rn2k2r/1ppbqp2/1p1p1n2/4p1B1/4P1pp/2PP4/PP2BPPP/R1Q1NRK1 w kq - 2 15


Prompt:
FEN: 7k/7p/8/8/3N4/8/8/7K 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=h1; queen=none; rook=none; bishop=none; knight=d4; pawn=none.
Black inventory: king=h8; queen=none; rook=none; bishop=none; knight=none; pawn=h7.


Prompt:
FEN: 5r2/pNp2kp1/1np2p2/4p1p1/2Pr4/1P1P3P/P3K2P/3R2R1 b - - 5 21
Count each piece type for both sides.

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

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


Prompt:
FEN: rn2kb1r/ppp1n2p/5p2/4p1p1/3pP3/BP1P1N1q/P1P2P1P/R2Q1RK1 b kq -
Convert the piece counts into material value totals.

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

White values: king=0; queen=9; rook=10; bishop=3; knight=3; pawn=7; total=32.
Black values: king=0; queen=9; rook=10; bishop=3; knight=6; pawn=8; total=36.


Prompt:
FEN: r7/p7/kpn5/3Q4/1p3P1P/8/P3N3/4K3 b - - 2 34
Trace inventory, counts, values, and material balance.

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

Inventory: white king=e1; queen=d5; rook=none; bishop=none; knight=e2; pawn=a2,f4,h4 | black king=a6; queen=none; rook=a8; bishop=none; knight=c6; pawn=b4,b6,a7
Counts: white king=1; queen=1; rook=0; bishop=0; knight=1; pawn=3 | black king=1; queen=0; rook=1; bishop=0; knight=1; pawn=3
Values: white total=15; black total=11
Balance: White is up 4 point(s) of material.


Prompt:
Starting FEN: r1bq1rk1/ppp2ppp/2n5/1BbPp3/4n3/P1p2N2/1P2NPPP/R1BQ1RK1 w - - 0 1
After the moves c1d2 d8f6, 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: r1b2rk1/ppp2ppp/2n2q2/1BbPp3/4n3/P1p2N2/1P1BNPPP/R2Q1RK1 w - - 2 2


Prompt:
Position (FEN): r2qkbnr/ppp2ppp/2n1b3/3pP3/3P4/8/PP3PPP/RNBQKBNR w KQkq -
Show me the board.


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

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

r4r1k/pbq1bppB/1pp1p3/4P3/2P3n1/2N1P3/PBQ2PPP/R4RK1 w - - 0 1


Prompt:
FEN: R7/6k1/P4r2/2K5/8/8/8/8 b - -
What piece is on f6?

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: rnbk1bnr/ppppq1pp/8/4pP1Q/5P2/6P1/PPPP3P/RNB1KBNR 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 (15 pieces): 2 bishops, 1 king, 2 knights, 7 pawns, 1 queen, 2 rooks. White is up 1 point(s) of material.


Prompt:
FEN: r1b3k1/ppp3pp/8/8/1n1p1Q2/2N4P/PPP1P3/2R2KN1 w - - 2 19
What is on h1?

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


Prompt:
FEN: 2r2rk1/1bq1bppp/p1n1pn2/6B1/N2P4/PB1Q1N2/5PPP/3RR1K1 w - -
What is the compressed FEN row for rank 5?

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


Prompt:
FEN: r5k1/1p4pp/3N2q1/p2np3/N3P1nP/6P1/PP2Q3/1K3R2 w - -
For square h2, give the FEN row-from-top and file index.

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

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


Prompt:
FEN: rr3k2/2pb2bp/3P2p1/2p5/PpB5/1P2RP2/K4P2/3R4 w - -
Compressed rank 3 row: 1P2RP2
Expand it into file cells a through h.

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


rn2k1nr/p3q1p1/2pp3p/1B2pb2/7P/5N2/PPP2PP1/RN1QK2R w KQkq - 0 11

Prompt:
Rank 1 row before: RN1QK2R
File d changes from Q to 1. Rewrite the compressed row.

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


rnb1k2r/pppp1ppp/8/4p3/4P2q/P2P1Q2/1PP2PP1/RN2KB1R b KQkq - 0 9

Prompt:
Board FEN before: rnb1k2r/pppp1ppp/8/4p3/4P2q/P2P1Q2/1PP2PP1/RN2KB1R
Apply square edits: h4 q->1; d8 1->q
Return the resulting board FEN only.

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

Result board FEN: rnbqk2r/pppp1ppp/8/4p3/4P3/P2P1Q2/1PP2PP1/RN2KB1R


Prompt:
Starting FEN: rnbq1rk1/ppp1bppp/4pn2/3p2B1/3P4/2PBP3/PP1N1PPP/R2QK1NR b KQ -
Move: b8d7
List the square lookups and rank edits.

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

Lookup: b8=black knight; d7=empty.
Squares: b8 black knight->empty; d7 empty->black knight.
Ranks: rank 8 b n->1; rank 7 d 1->n.


Prompt:
Starting FEN: r1b1k1nr/pp3pp1/2ppp3/8/2PPP3/2NQ2nP/PP1KNqB1/R1B3R1 w kq - 8 15
Move: a2a3
Use square lookups and rank edits to assemble the resulting full FEN.
State needed for full FEN:
Side to move: white
Castling rights: kq
En passant: none
Halfmove clock: 8
Fullmove number: 15

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

Move 1: white pawn a2a3.
Lookup: a2=white pawn; a3=empty.
Squares: a2 white pawn->empty; a3 empty->white pawn.
Ranks: rank 2 a P->1; rank 3 a 1->P.
Result FEN: r1b1k1nr/pp3pp1/2ppp3/8/2PPP3/P1NQ2nP/1P1KNqB1/R1B3R1 b kq - 0 15


Prompt:
Starting FEN: 6k1/3n1pp1/p5qp/8/4N3/2p2P2/6PP/Q5K1 b - - 1 33
Move: d7b8
Rewrite the affected compressed FEN rank rows and give Result FEN.
State needed for full FEN:
Side to move: black
Castling rights: none
En passant: none
Halfmove clock: 1
Fullmove number: 33

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


Prompt:
Starting FEN: 1kb5/p2r2b1/pp6/8/P6Q/1PN4P/2P2PP1/3RR1K1 w - - 0 1
After the moves e1f1, what is the resulting position?
State needed for full FEN:
Side to move: white
Castling rights: none
En passant: none
Halfmove clock: 0
Fullmove number: 1

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

Result FEN: 1kb5/p2r2b1/pp6/8/P6Q/1PN4P/2P2PP1/3R1RK1 b - - 1 1


Prompt:
FEN: 2krr3/1q1p2p1/p2R2n1/2p1npNp/2P1p2P/1PN3P1/P3QP2/4R1K1 b - - 3 26
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=e2; rook=e1,d6; bishop=none; knight=c3,g5; pawn=a2,f2,b3,g3,c4,h4.
Black inventory: king=c8; queen=b7; rook=d8,e8; bishop=none; knight=e5,g6; pawn=e4,c5,f5,h5,a6,d7,g7.


Prompt:
FEN: r1b2rk1/4nppp/2p5/p7/2NB4/2P5/P4PPP/R3K3 w - -
Count each piece type for both sides.

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

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


Prompt:
FEN: r1b2rk1/2q1bppp/2n1p3/ppPpP3/1Pp2P2/P1P1BN2/2Q1B1PP/R4RK1 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=6; knight=3; pawn=8; total=36.
Black values: king=0; queen=9; rook=10; bishop=6; knight=3; pawn=8; total=36.


Prompt:
FEN: 5rk1/5p1p/p1r1pqp1/2NpRn2/2pP1P2/2P4P/PP3QP1/1R4K1 b - - 6 26
Trace inventory, counts, values, and material balance.

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

Inventory: white king=g1; queen=f2; rook=b1,e5; bishop=none; knight=c5; pawn=a2,b2,g2,c3,h3,d4,f4 | black king=g8; queen=f6; rook=c6,f8; bishop=none; knight=f5; pawn=c4,d5,a6,e6,g6,f7,h7
Counts: white king=1; queen=1; rook=2; bishop=0; knight=1; pawn=7 | black king=1; queen=1; rook=2; bishop=0; knight=1; pawn=7
Values: white total=29; black total=29
Balance: Material is equal.


Prompt:
Starting FEN: r2qkbnr/pp3ppb/2n1p3/1BppP2N/3P2PP/2N5/PPP2P2/R1BQK2R b KQkq - 0 1
After the moves h7d3 f2f4, 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: r2qkbnr/pp3pp1/2n1p3/1BppP2N/3P1PPP/2Nb4/PPP5/R1BQK2R b KQkq - 0 2


Prompt:
Position (FEN): 8/6p1/3R3p/5pk1/1r6/5K2/5P1P/8 w - -
Show me the board.


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

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


Prompt:
FEN: rnbqk2r/ppp2ppp/4pn2/3p4/1b1P4/2N2N2/PPPBPPPP/R2QKB1R w KQkq - 4 5
What piece is on f7?

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


Prompt:
FEN: r4rk1/ppp3pp/4p3/7q/1b3P2/2N5/PP1BNQ1P/n4K1R b - - 0 19
What is the material count for both sides?

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


Prompt:
FEN: r1b2rk1/ppqn1ppp/5n2/2Pp4/5Q2/P1P1PN2/5PPP/R1B1KB1R b KQ -
What is on b7?

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


Prompt:
FEN: rnbq1rk1/p1p1ppbp/1p1p1np1/8/3P4/2NBPN1P/PPP2PP1/R1BQ1RK1 b - -
What is the compressed FEN row for rank 3?

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


Prompt:
FEN: rn1q1rk1/ppp2ppp/3b1n2/8/2BpPN2/3P1Q2/PPP3PP/R1B2RK1 b - - 0 10
For square e2, give the FEN row-from-top and file index.

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

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


Prompt:
FEN: r5k1/pp2q1pp/2p5/2bp1P2/6Q1/4r2P/PPP5/RN3R1K w - - 6 26
Compressed rank 2 row: PPP5
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: P3P3
File a changes from P to q. Rewrite the compressed row.

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


Prompt:
Board FEN before: 8/8/4B3/1k3P2/1P1R2K1/2r5/8/8
Apply square edits: f5 P->1; f6 1->P
Return the resulting board FEN only.

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


Prompt:
Starting FEN: 4k3/2r2p2/K3p3/2n5/4P3/1P6/P7/R7 w - -
Move: a6a5
List the square lookups and rank edits.

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

Lookup: a6=white king; a5=empty.
Squares: a6 white king->empty; a5 empty->white king.
Ranks: rank 6 a K->1; rank 5 a 1->K.


Prompt:
Starting FEN: rBbqk2r/pp3ppp/5n2/8/2pP4/2N5/PP2B1PP/R2Q1KNR b kq - 0 1
Move: h7h5
Use square lookups and rank edits to assemble the resulting full FEN.
State needed for full FEN:
Side to move: black
Castling rights: kq
En passant: none
Halfmove clock: 0
Fullmove number: 1

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

Move 1: black pawn h7h5.
Lookup: h7=black pawn; h5=empty.
Squares: h7 black pawn->empty; h5 empty->black pawn.
Ranks: rank 7 h p->1; rank 5 h 1->p.
Result FEN: rBbqk2r/pp3pp1/5n2/7p/2pP4/2N5/PP2B1PP/R2Q1KNR w kq - 0 2


Prompt:
Starting FEN: 8/6k1/8/r3NKPP/8/8/8/8 b - - 0 66
Move: a5d5
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: 66

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

Rows: rank 5 r3NKPP->3rNKPP.
Result FEN: 8/6k1/8/3rNKPP/8/8/8/8 w - - 1 67


Prompt:
Starting FEN: 8/8/8/8/2n5/2k5/K3Q3/8 w - - 0 1
After the moves e2f2, what is the resulting position?
State needed for full FEN:
Side to move: white
Castling rights: none
En passant: none
Halfmove clock: 0
Fullmove number: 1

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


Prompt:
FEN: 8/6kp/7q/8/6PK/8/8/q7 w - - 0 50
List the material inventory by side and piece type.

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

White inventory: king=h4; queen=none; rook=none; bishop=none; knight=none; pawn=g4.
Black inventory: king=g7; queen=a1,h6; rook=none; bishop=none; knight=none; pawn=h7.


Prompt:
FEN: rnbk1bnr/pppq1ppp/3P4/3N4/5p2/5N2/PPPPQ1PP/R1B1KB1R w 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=7.
Black counts: king=1; queen=1; rook=2; bishop=2; knight=2; pawn=7.


Prompt:
FEN: r4rk1/p1p2p1p/b1p1qnp1/4p3/2P2P2/NP6/P3BQPP/R4RK1 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=3; pawn=6; total=31.
Black values: king=0; queen=9; rook=10; bishop=3; knight=3; pawn=7; total=32.


Prompt:
FEN: 1R6/K7/7k/8/6R1/7P/6P1/8 w - - 1 48
Trace inventory, counts, values, and material balance.

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

Inventory: white king=a7; queen=none; rook=g4,b8; bishop=none; knight=none; pawn=g2,h3 | black king=h6; queen=none; rook=none; bishop=none; knight=none; pawn=none
Counts: white king=1; queen=0; rook=2; bishop=0; knight=0; pawn=2 | black king=1; queen=0; rook=0; bishop=0; knight=0; pawn=0
Values: white total=12; black total=0
Balance: White is up 12 point(s) of material.


Prompt:
Starting FEN: r1b4k/pp4bp/6p1/3QP3/5P1q/8/PP3P1P/R1B2RK1 w - - 1 20
After the moves d5c5 g7e5, 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: 20

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

Result FEN: r1b4k/pp5p/6p1/2Q1b3/5P1q/8/PP3P1P/R1B2RK1 w - - 0 21


Prompt:
Position (FEN): 8/2p1k2p/3b3q/5p2/Q2Ppp2/4P1N1/1P4PP/2B3K1 w - - 0 27
Show me the board.


Prompt:
Here is the current board:
8 . . r q r . . k
7 . . . n . . p p
6 . . . P . . p .
5 p . . . . . N .
4 . . . . . n . P
3 . Q . . . P . .
2 . P P . . B P .
1 R . . . . R K .
  a b c d e f g h
Write the FEN for this position.
State needed for full FEN:
Side to move: black
Castling rights: none
En passant: none
Halfmove clock: 2
Fullmove number: 27

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


Prompt:
FEN: 8/5k2/8/8/4p1P1/4K2P/8/8 w - -
What piece is on e3?

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


Prompt:
FEN: 1R6/8/8/8/5K2/8/R7/3k4 w - -
What is the material count for both sides?

White (3 pieces): 1 king, 2 rooks. Black (1 pieces): 1 king. White is up 10 point(s) of material.


Prompt:
FEN: 8/8/3kpp2/7p/7P/8/4KPP1/8 b - -
What is on d6?

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


Prompt:
FEN: rnbqkb1r/2p2ppp/p3pn2/2pp4/PP1P4/4P3/5PPP/RNBQKBNR w KQkq - 0 7
What is the compressed FEN row for rank 3?

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


Prompt:
FEN: 1k1r1r2/pp3q2/2p2n2/6Q1/3pNp2/P4P2/1PPB4/1K1R4 w - - 1 22
For square c7, 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>".

c7: file=c; rank=7; fen_row_from_top=2; file_index=3


Prompt:
FEN: 1R6/kp5r/3p1q2/p1pBp3/4P1p1/1R1PQ2P/PP4P1/6K1 b - - 5 31
Compressed rank 3 row: 1R1PQ2P
Expand it into file cells a through h.

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


rnbqk1nr/pppp2bp/5pp1/4p3/8/PP4P1/1BPPPPBP/RN1QK1NR b KQkq -

Prompt:
Rank 7 row before: pppp2bp
File e changes from 1 to k. Rewrite the compressed row.

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


r1b1kb1r/ppppqppp/2n2n2/4p1B1/3PP3/2PQ1N2/PP3PPP/RN2KB1R b KQkq -

Prompt:
Board FEN before: r1b1kb1r/ppppqppp/2n2n2/4p1B1/3PP3/2PQ1N2/PP3PPP/RN2KB1R
Apply square edits: c6 n->1; a5 1->n
Return the resulting board FEN only.

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

Result board FEN: r1b1kb1r/ppppqppp/5n2/n3p1B1/3PP3/2PQ1N2/PP3PPP/RN2KB1R


Prompt:
Starting FEN: r4k2/pp3r2/2n1PPQ1/2p4p/3p4/2P5/P5PP/5RK1 b - -
Move: a8e8
List the square lookups and rank edits.

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

Lookup: a8=black rook; e8=empty.
Squares: a8 black rook->empty; e8 empty->black rook.
Ranks: rank 8 a r->1; rank 8 e 1->r.


Prompt:
Starting FEN: 8/k1K5/8/1p5p/1P5P/8/8/8 w - - 0 1
Move: c7d8
Use square lookups and rank edits to assemble the resulting full FEN.
State needed for full FEN:
Side to move: white
Castling rights: none
En passant: none
Halfmove clock: 0
Fullmove number: 1

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

Move 1: white king c7d8.
Lookup: c7=white king; d8=empty.
Squares: c7 white king->empty; d8 empty->white king.
Ranks: rank 7 c K->1; rank 8 d 1->K.
Result FEN: 3K4/k7/8/1p5p/1P5P/8/8/8 b - - 1 1


Prompt:
Starting FEN: rnbqkb1r/pp2pppp/5n2/3p4/3N1B2/2N5/PPP1PPPP/R2QKB1R b KQkq - 0 1
Move: f6d7
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 6 5n2->8; rank 7 pp2pppp->pp1npppp.
Result FEN: rnbqkb1r/pp1npppp/8/3p4/3N1B2/2N5/PPP1PPPP/R2QKB1R w KQkq - 1 2


Prompt:
Starting FEN: 1rb1k1nr/pp3ppp/2n5/3Nq1N1/8/4B3/P4PPP/3QKB1R w Kk - 0 1
After the moves e1e2, what is the resulting position?
State needed for full FEN:
Side to move: white
Castling rights: Kk
En passant: none
Halfmove clock: 0
Fullmove number: 1

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

Result FEN: 1rb1k1nr/pp3ppp/2n5/3Nq1N1/8/4B3/P3KPPP/3Q1B1R b k - 1 1


Prompt:
FEN: 8/4k1p1/7p/5p2/1R3P2/8/6K1/7r b - - 3 44
List the material inventory by side and piece type.

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

White inventory: king=g2; queen=none; rook=b4; bishop=none; knight=none; pawn=f4.
Black inventory: king=e7; queen=none; rook=h1; bishop=none; knight=none; pawn=f5,h6,g7.


Prompt:
FEN: 2B5/p3bQ2/1k1p4/3Pp1p1/1p1qp3/2n5/5P2/5K2 b - - 7 43
Count each piece type for both sides.

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

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


Prompt:
FEN: r1b3k1/3p2pp/p4q2/5Q2/1p6/1P6/6PP/4R1K1 w - - 1 25
Convert the piece counts into material value totals.

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

White values: king=0; queen=9; rook=5; bishop=0; knight=0; pawn=3; total=17.
Black values: king=0; queen=9; rook=5; bishop=3; knight=0; pawn=5; total=22.


Prompt:
FEN: r4rk1/2qnb1pp/1pp2n2/2Pp1N2/pP1Pp3/P6P/2BB1PP1/R2Q1R1K b - - 1 20
Trace inventory, counts, values, and material balance.

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

Inventory: white king=h1; queen=d1; rook=a1,f1; bishop=c2,d2; knight=f5; pawn=f2,g2,a3,h3,b4,d4,c5 | black king=g8; queen=c7; rook=a8,f8; bishop=e7; knight=f6,d7; pawn=a4,e4,d5,b6,c6,g7,h7
Counts: white king=1; queen=1; rook=2; bishop=2; knight=1; pawn=7 | black king=1; queen=1; rook=2; bishop=1; knight=2; pawn=7
Values: white total=35; black total=35
Balance: Material is equal.


Prompt:
Starting FEN: 1n3rk1/rb2q1b1/1p2p2p/p2nP1p1/4Bp2/P2Q1PP1/1P2NB1P/2R2RK1 b - - 0 30
After the moves b8a6 f2e1, 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: 30

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

Result FEN: 5rk1/rb2q1b1/np2p2p/p2nP1p1/4Bp2/P2Q1PP1/1P2N2P/2R1BRK1 b - - 2 31


Prompt:
Position (FEN): 8/pp3kr1/8/6R1/3p1bb1/1P1B2P1/P2n1K2/7R w - - 0 34
Show me the board.


Prompt:
Here is the current board:
8 r . b . k . . r
7 . p . n b . p p
6 . . p . . p . .
5 . . . . p q . .
4 p . . P . . . .
3 P . Q . B N . .
2 . P P . B P P P
1 . . . R R . K .
  a b c d e f g h
Write the FEN for this position.
State needed for full FEN:
Side to move: black
Castling rights: kq
En passant: none
Halfmove clock: 0
Fullmove number: 16

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


Prompt:
FEN: r4r2/3n1p1k/2p1q2p/1pp1pR2/4Pp1P/pP1P1N1Q/P1P2P2/1K1R4 w - -
What piece is on h7?

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: r1bqkbnr/ppp2ppp/2n1p3/8/2BP4/4P3/PP3PPP/RNBQK1NR w KQkq - 0 5
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: 5rk1/pp1qrp1p/8/3pPpQ1/3P4/6R1/PP4PP/5R1K b - -
What is on f7?

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


Prompt:
FEN: r2q1rk1/4bppp/p2pbn2/1pp1p3/3nP3/P1NPNP2/BPP3PP/R1BQ1RK1 w - -
What is the compressed FEN row for rank 5?

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


Prompt:
FEN: r1bqk2r/p4ppp/2n2n2/2bp4/8/2PB4/P1Q2PPP/RNB1K1NR w KQkq - 0 10
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: r3kb1r/1ppbqp2/2np1npp/PB2p3/4P3/1QPP1N2/5PPP/RNB1K2R b KQkq - 0 11
Compressed rank 4 row: 4P3
Expand it into file cells a through h.

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


rn1qr1k1/3bppbp/3p2p1/p2P4/1pP5/5NP1/1P1QPP1P/R2NKB1R b KQ - 1 19

Prompt:
Rank 7 row before: 3bppbp
File g changes from b to 1. Rewrite the compressed row.

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


rn1kb2r/pp3ppp/2p1p3/3PN3/2P1p3/4P3/PP3PPP/R2QKB1R b KQ - 0 11

Prompt:
Board FEN before: rn1kb2r/pp3ppp/2p1p3/3PN3/2P1p3/4P3/PP3PPP/R2QKB1R
Apply square edits: a7 p->1; a5 1->p
Return the resulting board FEN only.

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

Result board FEN: rn1kb2r/1p3ppp/2p1p3/p2PN3/2P1p3/4P3/PP3PPP/R2QKB1R


Prompt:
Starting FEN: 2kr3r/pp3pp1/2p1p1b1/4P1Pp/7P/1B5n/PPPN1P2/2KR1R2 b - -
Move: g6e4
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=black bishop; e4=empty.
Squares: g6 black bishop->empty; e4 empty->black bishop.
Ranks: rank 6 g b->1; rank 4 e 1->b.


Prompt:
Starting FEN: r1bqk2r/pppp1ppp/2n2n2/b7/2P5/P7/1B1PPPPP/RN1QKBNR b KQkq - 0 1
Move: a5d2
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 bishop a5d2. Captures white pawn on d2.
Lookup: a5=black bishop; d2=white pawn.
Squares: a5 black bishop->empty; d2 white pawn->black bishop.
Ranks: rank 5 a b->1; rank 2 d P->b.
Result FEN: r1bqk2r/pppp1ppp/2n2n2/8/2P5/P7/1B1bPPPP/RN1QKBNR w KQkq - 0 2


Prompt:
Starting FEN: 8/7k/8/8/8/1K6/8/3q4 w - - 0 1
Move: b3b2
Rewrite the affected compressed FEN rank rows and give Result FEN.
State needed for full FEN:
Side to move: white
Castling rights: none
En passant: none
Halfmove clock: 0
Fullmove number: 1

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


Prompt:
Starting FEN: rnbq1rk1/ppp1bppp/4p3/3pP3/3P1P2/2NB4/PPP3PP/R2QK1NR b KQ - 2 8
After the moves h7h6, what is the resulting position?
State needed for full FEN:
Side to move: black
Castling rights: KQ
En passant: none
Halfmove clock: 2
Fullmove number: 8

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

Result FEN: rnbq1rk1/ppp1bpp1/4p2p/3pP3/3P1P2/2NB4/PPP3PP/R2QK1NR w KQ - 0 9


Prompt:
FEN: r3r3/8/1p6/pk2p2p/1P5P/8/3B2PK/4R3 w - - 0 37
List the material inventory by side and piece type.

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

White inventory: king=h2; queen=none; rook=e1; bishop=d2; knight=none; pawn=g2,b4,h4.
Black inventory: king=b5; queen=none; rook=a8,e8; bishop=none; knight=none; pawn=a5,e5,h5,b6.


Prompt:
FEN: r6k/pp1R2rp/1b6/3Q4/2p5/B6P/P4qPK/8 w - -
Count each piece type for both sides.

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

White counts: king=1; queen=1; rook=1; bishop=1; knight=0; pawn=3.
Black counts: king=1; queen=1; rook=2; bishop=1; knight=0; pawn=4.


Prompt:
FEN: 2kr3r/ppp1n1pp/8/4P3/1P2b3/8/PP1B2PP/2K1R2R w - - 0 19
Convert the piece counts into material value totals.

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

White values: king=0; queen=0; rook=10; bishop=3; knight=0; pawn=6; total=19.
Black values: king=0; queen=0; rook=10; bishop=3; knight=3; pawn=5; total=21.


Prompt:
FEN: r2qr1k1/ppp2ppp/2npbn2/2b5/2PP4/2N2NPP/PP3PB1/R1BQ1RK1 b - -
Trace inventory, counts, values, and material balance.

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

Inventory: white king=g1; queen=d1; rook=a1,f1; bishop=c1,g2; knight=c3,f3; pawn=a2,b2,f2,g3,h3,c4,d4 | black king=g8; queen=d8; rook=a8,e8; bishop=c5,e6; knight=c6,f6; pawn=d6,a7,b7,c7,f7,g7,h7
Counts: white king=1; queen=1; rook=2; bishop=2; knight=2; pawn=7 | black king=1; queen=1; rook=2; bishop=2; knight=2; pawn=7
Values: white total=38; black total=38
Balance: Material is equal.


Prompt:
Starting FEN: rnbqr1k1/pppp1ppp/8/8/4PQ2/2PP3N/P4PPP/bN2KB1R b K - 0 9
After the moves d7d6 a2a4, what is the resulting position?
State needed for full FEN:
Side to move: black
Castling rights: K
En passant: none
Halfmove clock: 0
Fullmove number: 9

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

Result FEN: rnbqr1k1/ppp2ppp/3p4/8/P3PQ2/2PP3N/5PPP/bN2KB1R b K - 0 10


Prompt:
Position (FEN): 5b1r/pk3ppp/bp3n2/8/2p2B2/P1N3PB/P3PP1P/1R1r2K1 w - - 0 22
Show me the board.


rn1qk2r/ppp1bppp/4pn2/3p1b2/2PP4/2N1PN2/PP1B1PPP/R2QKB1R b KQkq - 3 6

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

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


Prompt:
FEN: 5rk1/1b3ppQ/8/2RN4/8/8/5PPP/6K1 b - -
What piece is on h7?

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: 2q2rk1/Q1p2pp1/p5np/1pB5/2p5/P6P/2P2PP1/4R1K1 b - - 0 26
What is the material count for both sides?

White (9 pieces): 1 bishop, 1 king, 5 pawns, 1 queen, 1 rook. Black (11 pieces): 1 king, 1 knight, 7 pawns, 1 queen, 1 rook. Black is up 2 point(s) of material.


Prompt:
FEN: 4brk1/2q2pb1/p4np1/2Q1p1Np/1pP1P2P/3N1PP1/2PR4/1K1R4 b - -
What is on e8?

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


Prompt:
FEN: r2qkbnr/pp3ppp/2b1p3/2p1P3/3P1P2/5N2/PP1P2PP/RNBQK2R b KQkq - 0 8
What is the compressed FEN row for rank 6?

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


Prompt:
FEN: 2kr2nr/pppqb3/2n1p1pp/3pP3/3P1B2/2PB4/PPQ3PP/RN2K2R w KQ - 0 12
For square f1, 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>".

f1: file=f; rank=1; fen_row_from_top=8; file_index=6


Prompt:
FEN: r4k1r/4bppp/p3qn2/1p2p1B1/Q3P3/2N5/PP3PPP/R4RK1 w - - 0 16
Compressed rank 1 row: R4RK1
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>".


r1bq1rk1/1ppp1ppp/pbn2n2/P3p3/1PB1P3/1QPP4/5PPP/RNB1K1NR b KQ - 0 8

Prompt:
Board FEN before: r1bq1rk1/1ppp1ppp/pbn2n2/P3p3/1PB1P3/1QPP4/5PPP/RNB1K1NR
Apply square edits: b6 b->1; d4 1->b
Return the resulting board FEN only.

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

Result board FEN: r1bq1rk1/1ppp1ppp/p1n2n2/P3p3/1PBbP3/1QPP4/5PPP/RNB1K1NR


Prompt:
Starting FEN: 2r3k1/4bppp/1p2p3/8/1p1Nb3/P3P1P1/1R2BPP1/6K1 w - - 0 22
Move: g1f1
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; f1=empty.
Squares: g1 white king->empty; f1 empty->white king.
Ranks: rank 1 g K->1; rank 1 f 1->K.


Prompt:
Starting FEN: 3r1b1r/pp2pk1p/4b1p1/8/3nPPn1/2N5/PPP2QPP/R1B1K2R w - - 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: none
En passant: none
Halfmove clock: 0
Fullmove number: 1

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

Move 1: white rook 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: 3r1b1r/pp2pk1p/4b1p1/8/3nPPn1/2N5/PPP2QPP/R1B1KR2 b - - 1 1


Prompt:
Starting FEN: r4r2/p1k5/1qp5/3pn1p1/1P6/P1P1P2R/7Q/RN2K3 b Q - 1 27
Move: a8e8
Rewrite the affected compressed FEN rank rows and give Result FEN.
State needed for full FEN:
Side to move: black
Castling rights: Q
En passant: none
Halfmove clock: 1
Fullmove number: 27

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

Rows: rank 8 r4r2->4rr2.
Result FEN: 4rr2/p1k5/1qp5/3pn1p1/1P6/P1P1P2R/7Q/RN2K3 w Q - 2 28


Prompt:
Starting FEN: r5k1/pb1q1pp1/1p3b2/2pP2BQ/4R3/P5P1/1P3P1P/2R3K1 b - - 0 1
After the moves a8f8, what is the resulting position?
State needed for full FEN:
Side to move: black
Castling rights: none
En passant: none
Halfmove clock: 0
Fullmove number: 1

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


Prompt:
FEN: r1bq1nk1/pp3pbp/2p2np1/3pN1B1/3P4/P1NQ4/1PP2PPP/4RBK1 w - - 3 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=d3; rook=e1; bishop=f1,g5; knight=c3,e5; pawn=b2,c2,f2,g2,h2,a3,d4.
Black inventory: king=g8; queen=d8; rook=a8; bishop=g7,c8; knight=f6,f8; pawn=d5,c6,g6,a7,b7,f7,h7.


Prompt:
FEN: r1bqk2r/1pp2ppp/pbn5/1B1pP3/3P4/2P2N2/P4PPP/R1BQK2R 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=1; pawn=7.
Black counts: king=1; queen=1; rook=2; bishop=2; knight=1; pawn=7.


Prompt:
FEN: 2k2bnr/ppp1pppp/8/8/P7/r3KP2/6PP/8 w - - 1 21
Convert the piece counts into material value totals.

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

White values: king=0; queen=0; rook=0; bishop=0; knight=0; pawn=4; total=4.
Black values: king=0; queen=0; rook=10; bishop=3; knight=3; pawn=7; total=23.


Prompt:
FEN: r2qkb1r/pp1bnppp/2n1p3/3pP3/3P4/3B1N2/PP3PPP/RNBQK2R w KQkq - 3 8
Trace inventory, counts, values, and material balance.

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

Inventory: white king=e1; queen=d1; rook=a1,h1; bishop=c1,d3; knight=b1,f3; pawn=a2,b2,f2,g2,h2,d4,e5 | black king=e8; queen=d8; rook=a8,h8; bishop=d7,f8; knight=c6,e7; 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: r3k1nr/ppp2ppp/2n5/3qp3/1b1P4/2N1PP2/PP1B1P1P/R2QKB1R b KQkq - 0 1
After the moves b7b6 d1e2 b6b5, 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: r3k1nr/p1p2ppp/2n5/1p1qp3/1b1P4/2N1PP2/PP1BQP1P/R3KB1R w KQkq - 0 3


Prompt:
Position (FEN): 1rb2r1k/3n1p1p/p6P/q1pp2P1/1b3P2/2N5/PPPQ4/1K1R1B1R w - - 1 20
Show me the board.


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

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


Prompt:
FEN: rn1qk3/pp2b2p/2pp2r1/5p2/3P2p1/2PB4/PP1BQPPP/R3RNK1 w q - 0 16
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: 4rrk1/3bnp1p/p4Qp1/8/1p2BP1N/8/P5PP/5RK1 w - -
What is the material count for both sides?

White (9 pieces): 1 bishop, 1 king, 1 knight, 4 pawns, 1 queen, 1 rook. Black (10 pieces): 1 bishop, 1 king, 1 knight, 5 pawns, 2 rooks. White is up 3 point(s) of material.


Prompt:
FEN: rn1qkb1r/ppp2ppp/4pn2/8/2PP4/2NQ4/PP3PPP/R1B1K1NR w KQkq -
What is on e8?

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


Prompt:
FEN: 6k1/6pp/8/p2r4/6P1/2b1P2P/2N2P2/1R4K1 w - - 5 33
What is the compressed FEN row for rank 7?

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


Prompt:
FEN: 2kr2nr/ppp1pp1p/6p1/4b3/8/2P2B2/PP3PPP/RN2K2R b - - 0 12
For square e1, give the FEN row-from-top and file index.

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

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


Prompt:
FEN: Q5Q1/8/8/8/8/8/1PP3P1/R2K2k1 b - - 2 54
Compressed rank 1 row: R2K2k1
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: 3R2k1
File f changes from 1 to r. Rewrite the compressed row.

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


rn1qk1nr/pp4pp/3Pbp2/8/8/2N2N2/PPP2PPP/R1BQKB1R b KQkq - 0 8

Prompt:
Board FEN before: rn1qk1nr/pp4pp/3Pbp2/8/8/2N2N2/PPP2PPP/R1BQKB1R
Apply square edits: g7 p->1; g6 1->p
Return the resulting board FEN only.

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

Result board FEN: rn1qk1nr/pp5p/3Pbpp1/8/8/2N2N2/PPP2PPP/R1BQKB1R


Prompt:
Starting FEN: rnbq1rk1/pp2ppbp/3p1np1/2p5/3P1B2/2P1PN2/PP2BPPP/RN1QK2R w KQ -
Move: e3e4
List the square lookups and rank edits.

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

Lookup: e3=white pawn; e4=empty.
Squares: e3 white pawn->empty; e4 empty->white pawn.
Ranks: rank 3 e P->1; rank 4 e 1->P.


Prompt:
Starting FEN: r4rk1/5ppp/p1p5/1pb1p3/5q2/2P2P2/PP1NQP1P/1K1R3R b - - 1 19
Move: f4a4
Use square lookups and rank edits to assemble the resulting full FEN.
State needed for full FEN:
Side to move: black
Castling rights: none
En passant: none
Halfmove clock: 1
Fullmove number: 19

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

Move 1: black queen f4a4.
Lookup: f4=black queen; a4=empty.
Squares: f4 black queen->empty; a4 empty->black queen.
Ranks: rank 4 f q->1; rank 4 a 1->q.
Result FEN: r4rk1/5ppp/p1p5/1pb1p3/q7/2P2P2/PP1NQP1P/1K1R3R w - - 2 20


Prompt:
Starting FEN: rnbq1rk1/ppp1ppbp/5np1/3p4/8/3P1NP1/PPPNPPBP/R1BQ1RK1 b - - 0 1
Move: g7h8
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 7 ppp1ppbp->ppp1pp1p; rank 8 rnbq1rk1->rnbq1rkb.
Result FEN: rnbq1rkb/ppp1pp1p/5np1/3p4/8/3P1NP1/PPPNPPBP/R1BQ1RK1 w - - 1 2


Prompt:
Starting FEN: r4rk1/1b3pp1/2p3p1/p3p3/1P2N3/3P4/1P3PPP/R4RK1 b - - 0 22
After the moves f7f5, 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: 22

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


Prompt:
FEN: rnb1k2r/1Q3p1p/p2p2p1/1p2p3/4P1P1/P3B3/1PP1BP1P/R3K2R 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=b7; rook=a1,h1; bishop=e2,e3; knight=none; pawn=b2,c2,f2,h2,a3,e4,g4.
Black inventory: king=e8; queen=none; rook=a8,h8; bishop=c8; knight=b8; pawn=b5,e5,a6,d6,g6,f7,h7.


Prompt:
FEN: 8/2k1n1Q1/1rpn2q1/5p2/2B2P1p/4P2P/P4R2/6K1 w - - 8 38
Count each piece type for both sides.

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

White counts: king=1; queen=1; rook=1; bishop=1; knight=0; pawn=4.
Black counts: king=1; queen=1; rook=1; bishop=0; knight=2; pawn=3.


Prompt:
FEN: rn1k4/p4K2/5p2/1Nb1p1p1/1P6/3p4/Pr6/8 w - - 0 40
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=2; total=5.
Black values: king=0; queen=0; rook=10; bishop=3; knight=3; pawn=5; total=21.


Prompt:
FEN: 2rqr1k1/pb1n2bp/1p1N2p1/4p3/2P5/1P1B4/PB3PPP/R2QR1K1 b - - 0 17
Trace inventory, counts, values, and material balance.

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

Inventory: white king=g1; queen=d1; rook=a1,e1; bishop=b2,d3; knight=d6; pawn=a2,f2,g2,h2,b3,c4 | black king=g8; queen=d8; rook=c8,e8; bishop=b7,g7; knight=d7; pawn=e5,b6,g6,a7,h7
Counts: white king=1; queen=1; rook=2; bishop=2; knight=1; pawn=6 | black king=1; queen=1; rook=2; bishop=2; knight=1; pawn=5
Values: white total=34; black total=33
Balance: White is up 1 point(s) of material.


Prompt:
Starting FEN: rq2r1k1/p2nbppp/3pb3/2p5/1P2PB2/P1N3Q1/2P1B1PP/3R1R1K w - - 0 1
After the moves c3a4 d7e5, 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: rq2r1k1/p3bppp/3pb3/2p1n3/NP2PB2/P5Q1/2P1B1PP/3R1R1K w - - 2 2


Prompt:
Position (FEN): 4k3/8/5K2/8/8/8/6Q1/4r3 b - -
Show me the board.


r1b1kb1r/pp1p1ppp/1qn1pn2/8/3PP3/2N2N2/PP3PPP/1RBQKB1R b Kkq - 5 7

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

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


Prompt:
FEN: 2b2r2/r5k1/p2q1p2/1ppPp1p1/4P2p/2P3PP/PP2QR1B/5RK1 b - - 0 29
What piece is on f8?

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: 2rq1rk1/1b3pb1/p2p1Np1/1pn1p1Np/3BP2P/5P2/PPPQ2P1/1K1R1B1R b - -
What is the material count for both sides?

White (15 pieces): 2 bishops, 1 king, 2 knights, 7 pawns, 1 queen, 2 rooks. Black (14 pieces): 2 bishops, 1 king, 1 knight, 7 pawns, 1 queen, 2 rooks. White is up 3 point(s) of material.


Prompt:
FEN: r3kb1r/1pp1pppp/p2q1n2/3N3b/8/4BNPP/PPP1QPB1/R3K2R b KQkq -
What is on e5?

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


Prompt:
FEN: 8/8/8/5N2/4K2k/8/4Q3/8 b - -
What is the compressed FEN row for rank 7?

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


Prompt:
FEN: 5r1k/7p/2R5/8/5P2/2p1P2P/5KP1/3q4 b - -
For square h3, give the FEN row-from-top and file index.

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

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


Prompt:
FEN: 2rqk2r/3nbpp1/p2pbn2/1p2p3/4PP1p/1NNBB2P/PPPQ2P1/1K1R3R b k -
Compressed rank 2 row: PPPQ2P1
Expand it into file cells a through h.

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


Prompt:
Rank 2 row before: 5KPP
File f changes from K to 1. Rewrite the compressed row.

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


Prompt:
Board FEN before: 8/3k3n/8/5P2/8/3P2P1/P2N1P2/2KR4
Apply square edits: g3 P->1; g4 1->P
Return the resulting board FEN only.

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

Result board FEN: 8/3k3n/8/5P2/6P1/3P4/P2N1P2/2KR4


Prompt:
Starting FEN: 5k2/p5p1/1p1nB1K1/8/7P/P7/1P6/8 b - -
Move: f8e7
List the square lookups and rank edits.

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

Lookup: f8=black king; e7=empty.
Squares: f8 black king->empty; e7 empty->black king.
Ranks: rank 8 f k->1; rank 7 e 1->k.


Prompt:
Starting FEN: r7/3k2p1/4pn1p/3p4/3n2PP/1bbP1P2/1q5K/8 w - - 2 38
Move: h2h1
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: 2
Fullmove number: 38

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

Move 1: white king h2h1.
Lookup: h2=white king; h1=empty.
Squares: h2 white king->empty; h1 empty->white king.
Ranks: rank 2 h K->1; rank 1 h 1->K.
Result FEN: r7/3k2p1/4pn1p/3p4/3n2PP/1bbP1P2/1q6/7K b - - 3 38


Prompt:
Starting FEN: 2kr3r/pp5p/2p2p1P/2P1p3/3p1n2/P4Q2/2q2P2/3R1K1R b - - 0 32
Move: c2b3
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: 32

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

Rows: rank 2 2q2P2->5P2; rank 3 P4Q2->Pq3Q2.
Result FEN: 2kr3r/pp5p/2p2p1P/2P1p3/3p1n2/Pq3Q2/5P2/3R1K1R w - - 1 33


Prompt:
Starting FEN: 2kr1bnr/pbpn4/1p1pq3/4p1pp/2P5/2N2NB1/PPQ1BPPP/R3K2R b KQ - 5 13
After the moves c8b8, what is the resulting position?
State needed for full FEN:
Side to move: black
Castling rights: KQ
En passant: none
Halfmove clock: 5
Fullmove number: 13

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

Result FEN: 1k1r1bnr/pbpn4/1p1pq3/4p1pp/2P5/2N2NB1/PPQ1BPPP/R3K2R w KQ - 6 14


Prompt:
FEN: r2qkbnr/4pppp/p1n5/1p1p4/B2P2b1/4BN2/PPP2PPP/RN1QK2R w KQkq - 0 8
List the material inventory by side and piece type.

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

White inventory: king=e1; queen=d1; rook=a1,h1; bishop=e3,a4; knight=b1,f3; pawn=a2,b2,c2,f2,g2,h2,d4.
Black inventory: king=e8; queen=d8; rook=a8,h8; bishop=g4,f8; knight=c6,g8; pawn=b5,d5,a6,e7,f7,g7,h7.


Prompt:
FEN: rnb1kb1r/pp2ppp1/2p2n1p/8/3P4/2N2N1P/PPP1BPP1/R1B1K2R b KQkq - 0 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=0; rook=2; bishop=2; knight=2; pawn=7.
Black counts: king=1; queen=0; rook=2; bishop=2; knight=2; pawn=7.


Prompt:
FEN: 8/pp6/2p3p1/4p1k1/6P1/2P2K2/P1P4P/8 w - -
Convert the piece counts into material value totals.

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

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


Prompt:
FEN: rnbqk2r/pp3ppp/3Bpn2/3p4/3P4/5N2/PPPN1PPP/R2QKB1R b KQkq -
Trace inventory, counts, values, and material balance.

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

Inventory: white king=e1; queen=d1; rook=a1,h1; bishop=f1,d6; knight=d2,f3; pawn=a2,b2,c2,f2,g2,h2,d4 | black king=e8; queen=d8; rook=a8,h8; bishop=c8; knight=f6,b8; 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=1; knight=2; pawn=7
Values: white total=38; black total=35
Balance: White is up 3 point(s) of material.


Prompt:
Starting FEN: r2qrnk1/p3bppp/5n2/2pp4/8/P1BBPP1P/1P2NP2/2RQ1RK1 w - - 0 1
After the moves d3f5 d8b6, 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: r3rnk1/p3bppp/1q3n2/2pp1B2/8/P1B1PP1P/1P2NP2/2RQ1RK1 w - - 2 2


Prompt:
Position (FEN): r1b2rk1/ppq2ppp/3B4/5n2/2B5/5Q2/PPP2PPP/RN3RK1 b - - 0 12
Show me the board.


r4r1k/ppp3p1/1bnp2qp/3N1bB1/1PB3nP/P3PN2/2PQ1PP1/2KR3R w - - 0 17

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

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


Prompt:
FEN: 4R3/6kp/5bp1/2BB1n2/p1P5/P2r2P1/5PKP/8 b - -
What piece is on g6?

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


Prompt:
FEN: 8/8/8/p7/1p6/k7/2K5/7b w - - 0 68
What is the material count for both sides?

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


Prompt:
FEN: r2k4/1Rn5/3p1p2/p3pBp1/P1PPP2p/4BP2/7K/8 w - - 3 30
What is on d5?

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


Prompt:
FEN: 8/8/1k6/3K4/1P6/2P5/8/8 w - -
What is the compressed FEN row for rank 4?

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


Prompt:
FEN: 7b/pk1N1p1p/2p4B/3p4/8/5R2/PPr3PP/6K1 b - - 0 28
For square a3, 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>".

a3: file=a; rank=3; fen_row_from_top=6; file_index=1


Prompt:
FEN: r6r/2pk1p2/1bp1q3/p2pPbp1/Q2P4/BNP1R1Pp/P4P1P/R5K1 w - -
Compressed rank 6 row: 1bp1q3
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: 3K4
File a changes from 1 to p. Rewrite the compressed row.

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


rnbq1rk1/1pp2ppp/p3pn2/8/1bBPP3/P1NQ4/1P2NPPP/R1B1K2R b KQ - 0 9

Prompt:
Board FEN before: rnbq1rk1/1pp2ppp/p3pn2/8/1bBPP3/P1NQ4/1P2NPPP/R1B1K2R
Apply square edits: f6 n->1; e8 1->n
Return the resulting board FEN only.

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

Result board FEN: rnbqnrk1/1pp2ppp/p3p3/8/1bBPP3/P1NQ4/1P2NPPP/R1B1K2R


Prompt:
Starting FEN: 8/k1Q5/3K4/8/8/8/6b1/8 b - -
Move: a7a8
List the square lookups and rank edits.

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

Lookup: a7=black king; a8=empty.
Squares: a7 black king->empty; a8 empty->black king.
Ranks: rank 7 a k->1; rank 8 a 1->k.


Prompt:
Starting FEN: r1b2rk1/pp2qpbp/3pp1p1/2p5/3nPP2/2PPBNP1/PP1Q2BP/R4RK1 b - - 0 1
Move: h7h5
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 pawn h7h5.
Lookup: h7=black pawn; h5=empty.
Squares: h7 black pawn->empty; h5 empty->black pawn.
Ranks: rank 7 h p->1; rank 5 h 1->p.
Result FEN: r1b2rk1/pp2qpb1/3pp1p1/2p4p/3nPP2/2PPBNP1/PP1Q2BP/R4RK1 w - - 0 2


Prompt:
Starting FEN: r1b1k2r/ppp1q3/1bnp1n1p/4P1p1/2B2p2/2P4P/PP1N2P1/RNBQ1R1K b kq - 0 13
Move: c6b4
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: 13

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

Rows: rank 6 1bnp1n1p->1b1p1n1p; rank 4 2B2p2->1nB2p2.
Result FEN: r1b1k2r/ppp1q3/1b1p1n1p/4P1p1/1nB2p2/2P4P/PP1N2P1/RNBQ1R1K w kq - 1 14


Prompt:
Starting FEN: r2qr1k1/pp1bbppp/2n1pn2/2pp4/3PPB2/2PB1N2/PP1N1PPP/R2QR1K1 b - - 0 1
After the moves b7b5, 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: r2qr1k1/p2bbppp/2n1pn2/1ppp4/3PPB2/2PB1N2/PP1N1PPP/R2QR1K1 w - - 0 2


Prompt:
FEN: 8/8/p5pk/P6p/8/p2K3P/8/1N6 b - -
List the material inventory by side and piece type.

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

White inventory: king=d3; queen=none; rook=none; bishop=none; knight=b1; pawn=h3,a5.
Black inventory: king=h6; queen=none; rook=none; bishop=none; knight=none; pawn=a3,h5,a6,g6.


Prompt:
FEN: 7r/4kq1p/p2p2pQ/2p1p3/2P2P2/3P4/r6P/4R1RK w - - 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=1; rook=2; bishop=0; knight=0; pawn=4.
Black counts: king=1; queen=1; rook=2; bishop=0; knight=0; pawn=6.


Prompt:
FEN: r1bqkbnr/ppp2ppp/2n5/3p4/2PP4/P7/1P3PPP/RNBQKBNR b KQkq - 0 5
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: 8/8/8/8/7N/6K1/6B1/6k1 w - -
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=none; bishop=g2; knight=h4; pawn=none | black king=g1; 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: 6k1/1p5p/p3ppp1/3p4/r6P/3K4/2R2PP1/8 w - - 0 35
After the moves h4h5 g8h8 d3e2, 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: 35

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


Prompt:
Position (FEN): r2q1rk1/1b1nbpp1/pp1p1n1p/2pN4/2B1PB2/5N1P/PPP2PP1/R2QR1K1 w - - 0 13
Show me the board.


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

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


Prompt:
FEN: r2qkbnr/p5pp/2pp1p2/np2p3/B3P3/2P2Q1P/PP1P1PP1/RNB2RK1 w kq - 0 10
What piece is on h3?

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


Prompt:
FEN: N2k1b1r/p3nppp/1pnp4/1B2p3/4q3/1Q5P/PPPP1PP1/R1B1K2R w KQ - 0 12
What is the material count for both sides?

White (14 pieces): 2 bishops, 1 king, 1 knight, 7 pawns, 1 queen, 2 rooks. Black (13 pieces): 1 bishop, 1 king, 2 knights, 7 pawns, 1 queen, 1 rook. White is up 5 point(s) of material.


Prompt:
FEN: b7/4kp1p/4pp2/1p6/2p1P3/5N1P/1P2nPP1/3r1K2 w - - 0 21
What is on g3?

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


Prompt:
FEN: 7r/2q2pk1/1p3pb1/p3p2p/7P/6Q1/1P2BPP1/3R2K1 w - -
What is the compressed FEN row for rank 4?

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


Prompt:
FEN: 2b1kr2/8/2p5/1p1pp2N/r3n1p1/8/4BPPP/2R2RK1 b - - 3 27
For square e1, give the FEN row-from-top and file index.

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

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


Prompt:
FEN: 2k5/1p4b1/6p1/1p4Pp/1P3P2/P1p1P3/2K5/3R4 w - - 0 37
Compressed rank 1 row: 3R4
Expand it into file cells a through h.

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


rnbqkbnr/ppp2ppp/8/3p4/8/1P1BP3/PBP2PPP/RN1QK1NR b KQkq -

Prompt:
Rank 5 row before: 3p4
File f changes from 1 to b. Rewrite the compressed row.

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


1rb1k1nr/pp3ppp/2p1p3/8/1R2P3/3B4/P1PN1PPP/5RK1 b k -

Prompt:
Board FEN before: 1rb1k1nr/pp3ppp/2p1p3/8/1R2P3/3B4/P1PN1PPP/5RK1
Apply square edits: b7 p->1; b5 1->p
Return the resulting board FEN only.

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

Result board FEN: 1rb1k1nr/p4ppp/2p1p3/1p6/1R2P3/3B4/P1PN1PPP/5RK1


Prompt:
Starting FEN: rn1qkbnr/pb1p1ppp/1p2p3/2p5/2PP4/4PN2/PP3PPP/RNBQKB1R w KQkq - 1 5
Move: g2g4
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 pawn; g4=empty.
Squares: g2 white pawn->empty; g4 empty->white pawn.
Ranks: rank 2 g P->1; rank 4 g 1->P.


Prompt:
Starting FEN: 2r2rk1/5ppp/p2qp3/np1p3b/3Pn3/P1PBBN1P/1PQ2PP1/R4RK1 b - - 7 17
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: none
En passant: none
Halfmove clock: 7
Fullmove number: 17

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: 2r2rk1/5p1p/p2qp1p1/np1p3b/3Pn3/P1PBBN1P/1PQ2PP1/R4RK1 w - - 0 18


Prompt:
Starting FEN: 8/8/6r1/1P3R2/6p1/2K5/2P3k1/8 b - - 0 46
Move: g4g3
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: 46

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


Prompt:
Starting FEN: r2qr1k1/pp1n1ppp/2p2n2/2b5/2PQpP2/N2p2P1/PB1P1PBP/R3R1K1 w - - 8 15
After the moves h2h3, what is the resulting position?
State needed for full FEN:
Side to move: white
Castling rights: none
En passant: none
Halfmove clock: 8
Fullmove number: 15

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

Result FEN: r2qr1k1/pp1n1ppp/2p2n2/2b5/2PQpP2/N2p2PP/PB1P1PB1/R3R1K1 b - - 0 15


Prompt:
FEN: 5k2/5p2/3b1p2/2pKpB1p/1pPp4/1P6/2P1RN1P/r4r2 b - - 7 37
List the material inventory by side and piece type.

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

White inventory: king=d5; queen=none; rook=e2; bishop=f5; knight=f2; pawn=c2,h2,b3,c4.
Black inventory: king=f8; queen=none; rook=a1,f1; bishop=d6; knight=none; pawn=b4,d4,c5,e5,h5,f6,f7.


Prompt:
FEN: 8/R2k4/8/6p1/3K1pP1/4rP2/8/8 b - - 14 51
Count each piece type for both sides.

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

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


Prompt:
FEN: r2q1rk1/pp1n2pp/n1p1p3/2PpP1b1/3P4/PP3N2/3Q2PP/RN3RK1 w - - 0 16
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=6; pawn=7; total=32.
Black values: king=0; queen=9; rook=10; bishop=3; knight=6; pawn=7; total=35.


Prompt:
FEN: r2q1rk1/pp2bppp/2n2nb1/3pN3/6P1/1BNP3P/PPP2P2/R1BQ1RK1 w - - 1 12
Trace inventory, counts, values, and material balance.

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

Inventory: white king=g1; queen=d1; rook=a1,f1; bishop=c1,b3; knight=c3,e5; pawn=a2,b2,c2,f2,d3,h3,g4 | black king=g8; queen=d8; rook=a8,f8; bishop=g6,e7; knight=c6,f6; pawn=d5,a7,b7,f7,g7,h7
Counts: white king=1; queen=1; rook=2; bishop=2; knight=2; pawn=7 | black king=1; queen=1; rook=2; bishop=2; knight=2; pawn=6
Values: white total=38; black total=37
Balance: White is up 1 point(s) of material.


Prompt:
Starting FEN: r4rk1/pp3ppp/2p1q3/5b2/5P2/2RBP3/PP2Q1PP/5RK1 w - - 0 1
After the moves d3b1 f5h3, 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/pp3ppp/2p1q3/8/5P2/2R1P2b/PP2Q1PP/1B3RK1 w - - 2 2


Prompt:
Position (FEN): rn1qk2r/pbpppp1p/1p3np1/8/2P5/1PP1P3/P4PPP/R1BQKBNR w KQkq - 1 7
Show me the board.


r1bq1rk1/p1ppnppp/2p5/2b2N2/4P3/8/PPP2PPP/RNBQ1RK1 b - - 4 8

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

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


Prompt:
FEN: 4k2r/p2qbpp1/2p1p2p/B1P5/P2Pp3/3rP3/5PPP/RR4K1 b k - 1 18
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: 8/5pkp/6p1/p2q4/8/6PP/5P2/5K2 b - - 5 38
What is the material count for both sides?

White (4 pieces): 1 king, 3 pawns. Black (6 pieces): 1 king, 4 pawns, 1 queen. Black is up 10 point(s) of material.


Prompt:
FEN: 5rk1/ppq3pp/1npb1B2/3pp3/1P6/P1NP2P1/2PQRP1P/4R1K1 b - - 0 18
What is on f5?

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