This game is sponsored by Lucky Cat Terminal by Vericeive, the world's best public coin point of sale system.
This prototype ports the 72-cell geometry, cell names, and colors from the original Java project, with the corrected polar starting arrangement. Each army has K, Q, R, R in the four central cells around its pole. The default Option 1 follows the selected arrangement of eight pawns, two bishops and two knights in the surrounding twelve cells. Black mirrors White across the equator, with king under king; older formations remain available in the selector. White starts at the north pole and black at the south pole.
Choose a formation from the Starting position control. It starts a new game immediately; Undo restores the previous game and formation. New game repeats the current formation. Option 1 is the default for new visitors. Option 2 is the quietest starting candidate, with pawns at all four corners and both bishops and knights on the ring. The other setups remain experimental playtest candidates. Rooks and pawns removes both bishops and both knights from each army, leaving their corner cells empty; all eight pawns remain.
Rooks follow edge-connected ranks; bishops follow diagonals through shared corners. Queens combine both. Kings take one step of either kind. Knights leap two steps along a rank and one to the side, ignoring intervening pieces. Occupied cells block sliding moves. You cannot leave your king in check.
Every sliding move ends when it enters a triangle. Starting there, a piece may choose any appropriate exit. Knights may leap across them. Pawns can enter or leave a triangle only by capture.
Pawns advance away from their home pole toward the opposite pole. Each of the eight starting pawns in the selected formation may advance two cells on its first move, provided both cells are empty and the path does not cross a triangle. Ordinary en passant lasts one turn. A pawn promotes to queen, rook, bishop, or knight on any of the four central cells at the enemy pole.
The source describes some rules informally. This version chooses forward pawn edges by progress away from the home pole; forward diagonals are capture paths. Knights crossing a triangle may choose a non-returning continuation. These choices need comparison with the original physical game. For the corrected polar setup, this prototype permits a first double step for all eight pawns and uses the four enemy polar cells as the promotion zone; these remain conventions to review.
Castling and the README's unusual capture-skipping en passant are not implemented: neither is defined precisely enough in the source. Checkmate, stalemate, the fifty-move draw, and threefold repetition are enforced. Other insufficient-material draws are not detected.
Read the original rules ↗ · Geometry and patent diagrams ↗
Choose which side the computer plays, or turn it off for two-player games. The computer uses the same legal-move rules as human players. It searches up to two plies (its move and your reply), values material and pawn progress, and considers all four promotions. It is a simple opponent and will still make tactical mistakes. Computer move can also play one turn for either side. Undo normally takes back your move and the computer reply together; after undoing a computer opening, press Computer move to resume.
Play against the computer or together on one device. Drag the globe to rotate it, or switch to Both sides to see the whole board. Use Cell list for keyboard-accessible play. Undo restores the previous turn; New game resets the board.
