Move Generator Test Cases

Dice Chess has a large and complex state space due to multi-move sequences, dice rolls, and path-optimization rules. This page cataloging all our active test cases is generated dynamically to let developers and chess experts visually inspect, verify, and document each scenario.

1-Die Scenarios

Move generator tests with a single die rolled. These represent the fundamental building blocks of legal move filtering.

1. Initial position: pawn moves

Standard starting position. With a Pawn (1) rolled, any white pawn can advance one or two squares forward.

Active Color: White
Castling Rights: Kingside & Queenside
Dice Rolled: ⚀ Pawn (1)
Expected Legal Moves: a2a3, a2a4, b2b3, b2b4, c2c3, c2c4, d2d3, d2d4, e2e3, e2e4, f2f3, f2f4, g2g3, g2g4, h2h3, h2h4
FEN: rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1 P

2. King only under Rook roll

The active player only has a King on the board. With a Rook (4) rolled, there are no rooks to move, and the King cannot act as a Rook. No legal moves are generated.

Active Color: White
Dice Rolled: ⚃ Rook (4)
Expected Legal Moves: None (no legal moves)
FEN: 4k3/8/8/8/8/8/8/4K3 w - - 0 1 R

3. King on the first row

The King is located on e1 with no other pieces on the board. Under a King (6) roll, all standard adjacent moves are legal.

Active Color: White
Dice Rolled: ⚅ King (6)
Expected Legal Moves: e1d1, e1d2, e1e2, e1f2, e1f1
FEN: 4k3/8/8/8/8/8/8/4K3 w - - 0 1 K

4. Queen moves from f3

The Queen is on f3 in a semi-open board. Under a Queen (5) roll, it can move along any unobstructed diagonal, rank, or file.

Active Color: White
Castling Rights: Kingside & Queenside
Dice Rolled: ⚄ Queen (5)
Expected Legal Moves: f3d1, f3e2, f3g4, f3h5, f3a3, f3b3, f3c3, f3d3, f3e3, f3g3, f3h3, f3f4, f3f5, f3f6, f3f7
FEN: rnbqkbnr/pppppppp/8/8/2B1P3/5Q2/PPPP1PPP/RNB1K1NR w KQkq - 0 1 Q

5. En Passant and Path Blockage

A complex pawn scenario: the pawn on e5 can capture the black d5 pawn en passant (exd6). The c2 pawn's two-square advance is blocked by the bishop on c4, so only c2-c3 is legal. The f2 pawn is completely blocked by the queen on f3.

Active Color: White
Castling Rights: Kingside & Queenside
En Passant Target: d6
Dice Rolled: ⚀ Pawn (1)
Expected Legal Moves: a2a3, a2a4, b2b3, b2b4, c2c3, d2d3, d2d4, e5e6, e5d6, g2g3, g2g4, h2h3, h2h4
FEN: rnbqkbnr/ppp1pppp/8/3pP3/2B5/5Q2/PPPP1PPP/RNB1K1NR w KQkq d6 0 1 P

6. En Passant, Pawn Choices, and Forward Blockage

The C pawn can either capture or move forward one square. The D pawn can move one or two squares forward, exposing the white king to check. The E pawn can capture en passant or take the knight, but cannot move forward.

Active Color: White
Castling Rights: Kingside & Queenside
En Passant Target: d6
Dice Rolled: ⚀ Pawn (1)
Expected Legal Moves: a2a3, a2a4, c4c5, c4d5, d2d3, d2d4, e5d6, e5f6, g2g3, g2g4
FEN: r1bqk2r/ppp2ppp/2n1pn2/3pP3/1bP5/1P3Q1N/PB1P1PPP/RN2KB1R w KQkq d6 0 1 P

7. Pawn promotion

A pawn on the seventh rank can advance to the eighth rank and promote to any piece (usually a queen). In this case, with a roll of 1, the only legal move is d7d8, which results in a pawn promotion.

Active Color: White
Dice Rolled: ⚀ Pawn (1)
Expected Legal Moves: d7d8b, d7d8n, d7d8q, d7d8r
FEN: 5k2/3P4/2K5/8/8/8/8/8 w - - 0 1 P

8. King and pawn, king move

A pawn on the seventh rank can advance to the eighth rank and promote to any piece (usually a queen). In this case, with a roll of 6, the king moves.

Active Color: White
Dice Rolled: ⚅ King (6)
Expected Legal Moves: c6b5, c6b6, c6b7, c6c5, c6c7, c6d5, c6d6
FEN: 5k2/3P4/2K5/8/8/8/8/8 w - - 0 1 K

9. Pawn promotion or capture

With a roll of Pawn (1), the pawn on d7 can promote to any piece on d8, or capture the black king on e8.

Active Color: White
Dice Rolled: ⚀ Pawn (1)
Expected Legal Moves: d7d8b, d7d8n, d7d8q, d7d8r, d7e8
FEN: 4k3/3P4/8/2K5/8/8/8/8 w - - 0 1 P

10. Three en passant targets

In this position, there are three en passant targets: a6, c6, and e6. The pawn on b5 can capture the pawn on a5 en passant (b5a6), or the pawn on c5 en passant (b5c6). The pawn on d5 can capture the pawn on c5 en passant (d5c6), or the pawn on e5 en passant (d5e6). Additionally, both pawns can move forward one square, and the g2 pawn can move one or two squares forward.

Active Color: White
Castling Rights: Kingside only
En Passant Targets: a6, c6, e6
Dice Rolled: ⚀ Pawn (1)
Expected Legal Moves: b5b6, b5a6, b5c6, d5c6, d5d6, d5e6, g2g3, g2g4
FEN: rnbqkbnr/1p1p1ppp/8/pPpPp3/P3P3/2N2Q1N/2P2PPP/1RB1KB1R w Kkq a6c6e6 0 1 P

2-Dice Scenarios

Move generator tests with two dice rolled. These evaluate intermediate micro-move sequences.

1. Initial position: pawn and knight moves

Starting position with two dice rolled: Pawn (1) and Knight (2). Since no micro-move can block another in the initial turn, the legal moves are the sum of all individual legal pawn moves and all individual legal knight moves.

Active Color: White
Castling Rights: Kingside & Queenside
Dice Rolled: ⚀ Pawn (1), ⚁ Knight (2)
Expected Legal Moves: a2a3, a2a4, b2b3, b2b4, c2c3, c2c4, d2d3, d2d4, e2e3, e2e4, f2f3, f2f4, g2g3, g2g4, h2h3, h2h4, b1a3, b1c3, g1f3, g1h3
FEN: rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1 PN

2. Short castling

Short castling is possible in this position

Active Color: White
Castling Rights: Kingside & Queenside
Dice Rolled: ⚃ Rook (4), ⚅ King (6)
Expected Legal Moves: e1e2, e1f1, a1b1, h1f1, h1g1, e1g1
FEN: r1b1k1nr/pppp1ppp/2n1pq2/8/1bB1P3/2N2N2/PPPP1PPP/R1BQK2R w KQkq - 0 1 RK

3. Long castling

Long castling is possible in this position

Active Color: White
Castling Rights: Kingside & Queenside
Dice Rolled: ⚃ Rook (4), ⚅ King (6)
Expected Legal Moves: e1d1, e1d2, a1b1, a1c1, a1d1, e1c1
FEN: r1bqk1nr/ppppbppp/2n5/6B1/3Q4/5N2/PPP1PPPP/R3KBNR w KQkq - 0 1 RK

4. Force promotion to knight

Forcing a pawn to promote to a knight in this position

Active Color: White
Dice Rolled: ⚀ Pawn (1), ⚁ Knight (2)
Expected Legal Moves: f7f8n
FEN: 3k4/5P2/2P5/8/5K2/8/8/8 w - - 0 1 PN

5. Force promotion to bishop

Forcing a pawn to promote to a bishop in this position

Active Color: White
Dice Rolled: ⚀ Pawn (1), ⚂ Bishop (3)
Expected Legal Moves: f7f8b
FEN: 3k4/5P2/2P5/8/5K2/8/8/8 w - - 0 1 PB

6. Force promotion to rook

Forcing a pawn to promote to a rook in this position

Active Color: White
Dice Rolled: ⚀ Pawn (1), ⚃ Rook (4)
Expected Legal Moves: f7f8r
FEN: 3k4/5P2/2P5/8/5K2/8/8/8 w - - 0 1 PR

7. Force promotion to queen

Forcing a pawn to promote to a queen in this position

Active Color: White
Dice Rolled: ⚀ Pawn (1), ⚄ Queen (5)
Expected Legal Moves: f7f8q
FEN: 3k4/5P2/2P5/8/5K2/8/8/8 w - - 0 1 PQ

8. Beat the King or force promotion to knight

Beat the King (1 micro move) or forcing a pawn to promote to a knight in this position (2 micro moves). Both options are legal and the player can choose which one to execute.

Active Color: White
Dice Rolled: ⚀ Pawn (1), ⚁ Knight (2)
Expected Legal Moves: c6d7, f7f8n
FEN: 8/3k1P2/2P5/8/5K2/8/8/8 w - - 0 1 PN

9. Beat the King or force promotion to bishop

Beat the King (1 micro move) or forcing a pawn to promote to a bishop in this position (2 micro moves). Both options are legal and the player can choose which one to execute.

Active Color: White
Dice Rolled: ⚀ Pawn (1), ⚂ Bishop (3)
Expected Legal Moves: c6d7, f7f8b
FEN: 8/3k1P2/2P5/8/5K2/8/8/8 w - - 0 1 PB

10. Beat the King or force promotion to rook

Beat the King (1 micro move) or forcing a pawn to promote to a rook in this position (2 micro moves). Both options are legal and the player can choose which one to execute.

Active Color: White
Dice Rolled: ⚀ Pawn (1), ⚃ Rook (4)
Expected Legal Moves: c6d7, f7f8r
FEN: 8/3k1P2/2P5/8/5K2/8/8/8 w - - 0 1 PR

11. Beat the King or force promotion to queen

Beat the King (1 micro move) or forcing a pawn to promote to a queen in this position (2 micro moves). Both options are legal and the player can choose which one to execute.

Active Color: White
Dice Rolled: ⚀ Pawn (1), ⚄ Queen (5)
Expected Legal Moves: c6d7, f7f8q
FEN: 8/3k1P2/2P5/8/5K2/8/8/8 w - - 0 1 PQ

12. The king can castle out of check

In this position, the white king is in check from the black bishop on g3. However, the king can still castle to escape the check. The legal moves include both the king's possible moves and the castling move, which allows the king to move two squares towards the rook and the rook to move to the square next to the king on the opposite side.

Active Color: White
Castling Rights: Kingside only
Dice Rolled: ⚃ Rook (4), ⚅ King (6)
Expected Legal Moves: e1d1, e1d2, e1e2, e1f1, e1f2, h1f1, h1g1, e1g1, h1h2, h1h3, h1h4, h1h5, h1h6, h1h7, h1h8
FEN: 4k3/8/8/8/8/6b1/8/4K2R w K - 0 1 RK

13. The king can castle out of check (long castling)

In this position, the white king is in check from the black bishop on b4. However, the king can still castle to escape the check. The legal moves include both the king's possible moves and the castling move, which allows the king to move two squares towards the rook and the rook to move to the square next to the king on the opposite side.

Active Color: White
Castling Rights: Queenside only
Dice Rolled: ⚃ Rook (4), ⚅ King (6)
Expected Legal Moves: e1d1, e1d2, e1e2, e1f1, e1f2, a1b1, a1c1, a1d1, e1c1, a1a2, a1a3, a1a4, a1a5, a1a6, a1a7, a1a8
FEN: 4k3/8/8/8/1b6/8/8/R3K3 w Q - 0 1 RK

14. After short castling, the king may be in check

In Dice Chess, after a short castling, the king can end up in check and this will be considered a legal move.

Active Color: White
Castling Rights: Kingside only
Dice Rolled: ⚃ Rook (4), ⚅ King (6)
Expected Legal Moves: e1d1, e1d2, e1e2, e1f1, e1f2, h1f1, h1g1, e1g1, h1h2, h1h3, h1h4, h1h5, h1h6, h1h7, h1h8
FEN: 4k3/8/8/2b5/8/8/8/4K2R w K - 0 1 RK

15. After long castling, the king may be in check

In Dice Chess, after a long castling, the king can end up in check and this will be considered a legal move.

Active Color: White
Castling Rights: Queenside only
Dice Rolled: ⚃ Rook (4), ⚅ King (6)
Expected Legal Moves: e1d1, e1d2, e1e2, e1f1, e1f2, a1b1, a1c1, a1d1, e1c1, a1a2, a1a3, a1a4, a1a5, a1a6, a1a7, a1a8
FEN: 4k3/8/8/6b1/8/8/8/R3K3 w Q - 0 1 RK

16. Only short castling is possible

In this position the rook on square A1 has already made a move and therefore only short castling is possible.

Active Color: White
Castling Rights: Kingside only
Dice Rolled: ⚃ Rook (4), ⚅ King (6)
Expected Legal Moves: e1d1, e1d2, e1e2, e1f1, e1f2, h1f1, h1g1, e1g1, h1h2, h1h3, h1h4, h1h5, h1h6, h1h7, h1h8, a1b1, a1c1, a1d1, a1a2, a1a3, a1a4, a1a5, a1a6, a1a7, a1a8
FEN: 4k3/8/8/8/8/8/8/R3K2R w K - 0 1 RK

17. Only long castling is possible

In this position the rook on square H1 has already made a move and therefore only long castling is possible.

Active Color: White
Castling Rights: Queenside only
Dice Rolled: ⚃ Rook (4), ⚅ King (6)
Expected Legal Moves: e1d1, e1d2, e1e2, e1f1, e1f2, h1f1, h1g1, e1c1, h1h2, h1h3, h1h4, h1h5, h1h6, h1h7, h1h8, a1b1, a1c1, a1d1, a1a2, a1a3, a1a4, a1a5, a1a6, a1a7, a1a8
FEN: 4k3/8/8/8/8/8/8/R3K2R w Q - 0 1 RK

18. Both castling options are possible

In this position both rooks and the king have not made a move and therefore both short and long castling are possible.

Active Color: White
Castling Rights: Kingside & Queenside
Dice Rolled: ⚃ Rook (4), ⚅ King (6)
Expected Legal Moves: e1d1, e1d2, e1e2, e1f1, e1f2, h1f1, h1g1, e1c1, e1g1, h1h2, h1h3, h1h4, h1h5, h1h6, h1h7, h1h8, a1b1, a1c1, a1d1, a1a2, a1a3, a1a4, a1a5, a1a6, a1a7, a1a8
FEN: 4k3/8/8/8/8/8/8/R3K2R w KQ - 0 1 RK

19. en passant is not possible on own pawn

In this position, the white pawn on b4 has just moved two squares forward from b2 to b4. However, the en passant capture is not possible for the white pawn on a2 because it cannot capture its own piece. Therefore, the legal moves for the white player are limited to moving the pawns on a2 and h2.

Active Color: White
Castling Rights: Kingside & Queenside
Dice Rolled: ⚀ Pawn (1), ⚃ Rook (4)
Expected Legal Moves: a2a3, a2a4, h2h3, h2h4
FEN: rnbqkbnr/pppppppp/8/8/1P6/8/P1PPPPPP/RNBQKBNR w KQkq - 0 1 PR

3-Dice Scenarios

Move generator tests with all three dice rolled. These verify full turn execution and complete path optimization.

1. Initial position: path optimization filter

Starting position with all three dice rolled: Pawn (1), Knight (2), and Bishop (3). According to the Dice Chess maximum micro-moves rules, quiet a/c/f/h pawn moves are completely filtered out because they do not form or enable a valid 3-move sequence (e.g. Pawn -> Bishop -> Knight).

Active Color: White
Castling Rights: Kingside & Queenside
Dice Rolled: ⚀ Pawn (1), ⚁ Knight (2), ⚂ Bishop (3)
Expected Legal Moves: b2b3, b2b4, d2d3, d2d4, e2e3, e2e4, g2g3, g2g4, b1a3, b1c3, g1f3, g1h3
FEN: rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1 PNB

2. Pawns with three dice

In this position, the white pawn on d5 can move to c6, d6, or e6 using one of the '1' dice. The white pawn on e7 can promote to a knight, bishop, queen, or rook on d8, e8, or f8 using the remaining two '1' dice.

Active Color: White
En Passant Target: c6
Dice Rolled: ⚀ Pawn (1), ⚀ Pawn (1), ⚀ Pawn (1)
Expected Legal Moves: b2b3, b2b4, d5c6, d5d6, d5e6, e7d8n, e7d8b, e7d8q, e7d8r, e7e8n, e7e8b, e7e8q, e7e8r, e7f8n, e7f8b, e7f8q, e7f8r
FEN: k2n1q2/1p2Pp2/4r3/2pP4/8/8/1PK5/8 w - c6 0 1 PPP

3. Casting and bishop moves with three dice

In this position, the black king on e8 can castle kingside to g8, or move to f8. The black bishop on e7 can move to f8, d6, c5, b4, or a3. The black rook on a8 can move to b8

Active Color: Black
Castling Rights: Kingside & Queenside
Dice Rolled: ⚂ Bishop (3), ⚃ Rook (4), ⚅ King (6)
Expected Legal Moves: e8f8, e8g8, h8g8, h8f8, e7f8, e7d6, e7c5, e7b4, e7a3, a8b8
FEN: r1bqk2r/ppppbppp/2n1pn2/1B6/3PP3/2N5/PPP2PPP/R1BQK1NR b KQkq - 0 1 brk

4. Force promotion to knight or bishop

Forcing a pawn to promote to a knight or bishop. Maximum two micro moves in this position.

Active Color: White
Dice Rolled: ⚀ Pawn (1), ⚁ Knight (2), ⚂ Bishop (3)
Expected Legal Moves: e7e8n, e7e8b
FEN: 8/4P3/5K2/8/2k5/8/1P6/8 w - - 0 1 PNB

5. Force promotion to knight or rook

Forcing a pawn to promote to a knight or rook. Maximum two micro moves in this position.

Active Color: White
Dice Rolled: ⚀ Pawn (1), ⚁ Knight (2), ⚃ Rook (4)
Expected Legal Moves: e7e8n, e7e8r
FEN: 8/4P3/5K2/8/2k5/8/1P6/8 w - - 0 1 PNR

6. Force promotion to knight or queen

Forcing a pawn to promote to a knight or queen. Maximum two micro moves in this position.

Active Color: White
Dice Rolled: ⚀ Pawn (1), ⚁ Knight (2), ⚄ Queen (5)
Expected Legal Moves: e7e8n, e7e8q
FEN: 8/4P3/5K2/8/2k5/8/1P6/8 w - - 0 1 PNQ

7. Force promotion to knight only

Forcing a pawn to promote to a knight only.

Active Color: White
Dice Rolled: ⚀ Pawn (1), ⚁ Knight (2), ⚅ King (6)
Expected Legal Moves: e7e8n, f6f7, f6f5, f6e5, f6g5, f6e6, f6g6, f6g7
FEN: 8/4P3/5K2/8/2k5/8/1P6/8 w - - 0 1 PNK

8. Beat the king or promote to a knight

We can beat the king or promote to a knight. Two or three micro moves in this position.

Active Color: White
Dice Rolled: ⚀ Pawn (1), ⚀ Pawn (1), ⚁ Knight (2)
Expected Legal Moves: e7e8n, b2b3, b2b4
FEN: 8/4P3/5K2/8/2k5/8/1P6/8 w - - 0 1 PPN

9. Bishop and king moves with three dice

In this position, the black king on e8 can move to f8 or d8. The black bishop on d7 can move to c6, b5, a4, e6, f5, g4, or h3.

Active Color: Black
Castling Rights: Kingside & Queenside
Dice Rolled: ⚂ Bishop (3), ⚅ King (6), ⚅ King (6)
Expected Legal Moves: e8f8, e8d8, d7c6, d7b5, d7a4, d7e6, d7f5, d7g4, d7h3
FEN: rnq1k2r/pppbpp1p/3p2pQ/8/2BPP3/2N2N2/PPPK1PPP/1R5R b kq - 0 1 BKK

10. One pawn promotion with three pawn’s dice

In this position, the white pawn on a7 can promote to a knight, bishop, queen, or rook on a8 using the three '1' dice.

Active Color: White
Dice Rolled: ⚀ Pawn (1), ⚀ Pawn (1), ⚀ Pawn (1)
Expected Legal Moves: a7a8n, a7a8b, a7a8q, a7a8r
FEN: 8/P7/8/8/8/8/8/k6K w - - 0 1 PPP