Single Rule Change
- Sideways Pawn Move: A pawn may move one square horizontally (left or right) to an empty square on the same rank. This move is not a capture.
Captures, Promotion, and Special Moves
- Pawns still capture one square forward diagonally (as in classical chess).
- Promotion, en passant (as usual for two‑step forward moves), castling, check, checkmate, stalemate, threefold repetition, and the 50‑move rule remain unchanged.
- A sideways pawn move resets the 50‑move counter (it is a pawn move).
Notation
Use a hyphen to indicate lateral movement. Example: c4-b4 or e5-f5. Captures are recorded normally (e.g., exd5).
Intent
This minimalist rule adds flexibility to pawn structures, unlocking fresh tactics and reducing rote opening reliance while preserving the spirit of classical chess.
See the comparison vs. classical chess →