Touch or click a piece, then a highlighted square. Keyboard: focus the board, use arrows to choose a square and Enter or Space to select; Escape clears selection. To castle, select your king and then its rook. The final g/c square also works unless it is a legal ordinary king move. Choose a piece when a pawn promotes, or include q/r/b/n in UCI input. Two humans can play hot-seat. Black-only human play faces Black; Flip board changes the view.
Bots get 1 s per move and forfeit on illegal or late moves, exceptions or loading failures. If both bots fail to load, the game is drawn. Pacing changes display speed, not thinking time. Games also end on checkmate, stalemate, automatic threefold repetition, the automatic fifty-move rule, insufficient material or the 400-ply limit. Series alternate colours; each pair shares its Chess960 position and participant random seeds. See all players.
Write your own bot: read the Bot API. Choose Your bot (upload…) to load a .js file up to 256 KB, kept only in this page's memory. Only load code you trust. Top-level bot code must not depend on Math.random; seeded randomness is available inside move(state).
The players
The Aizanoi sample bots are house examples, not AI-model benchmark entries.