Explosive Chess

1. Standard Chess Rules Apply

With the following alterations:

• Checkmate/stalemate determination accounts for the new piece rook-pawn and the new moves: explode, shoot, pawnify, teleport, fort, and stargate.
• Any black pawns on the 7th rank and white pawns on the 2nd rank may move forward one or two squares, regardless of how they got there.
• A pawn displaced to the opponent's back rank auto-promotes immediately.
• Promotion allows choosing a piece of either color. An opponent-colored piece is controlled by the opponent.

2. Explode

A player may cast explode on their own knight or queen.

Knight Explosion

The knight is removed. All non-king pieces in the surrounding 8 squares are displaced one square radially outward (away from the knight). Pieces sent off the board or to an occupied square are removed. All displacements are simultaneous.

Queen Explosion

The queen is removed. The player chooses a line (rank, file, or diagonal). All pieces on that entire line are destroyed, except kings.

An original queen cannot explode until she has moved at least once. Promoted queens have no such restriction.

3. Shoot

A player may cast shoot on one of their bishops and a diagonally adjacent pawn or knight of their color.

Bishop + Pawn

The pawn is shot outward along the diagonal. On collision, both the pawn and target are removed (kings unaffected). If no collision, the pawn leaves the board.

Bishop + Knight

The knight is shot outward along the diagonal. On collision, the target is removed, the knight takes its place, then the knight explodes (as per knight explosion rules). If the target was a king, the king is restored after the explosion.

4. Pawnify

If a rook is one square behind a friendly pawn, the player may cast pawnify. The pawn is removed and the rook becomes a rook-pawn.

Rook-Pawn Properties

• Moves like a rook (any direction along rank/file)
• Can also capture diagonally forward like a pawn
• Can castle like a normal rook
• Cannot perform en passant
• Never promotes

5. Teleport

Once per game, each player may teleport their king to any empty square not in check.

• Cannot teleport out of check
• If the only legal move is teleport, you must teleport

6. Fort

Cast fort on your king if:

• King is not on the board edge
• Only friendly pawns (or empty) surround the king, with at least one pawn present
• Every friendly pawn is either captured or adjacent to the king

All captured pawns are revived and placed around the king (8 pawns total). Once per game.

7. Stargate

Choose two friendly pawns forming an axis-aligned rectangle (different rank and file). All pieces inside the rectangle (not on boundary) are vaporized, except kings.

• No pieces may be on the rectangle boundary besides the two pawns
• Must actually vaporize at least one non-king piece

Check Escape

All special moves except teleport can be used to escape check.

Notation