Crazyhouse: captured pieces return to play
Crazyhouse uses one board. Each captured piece changes colour and enters your reserve. Instead of a normal move you may place it on an empty square. Kaissa offers standard 1v1 and the club's own team 2v2 format.
Two formats, one board
1v1 — two players, each controlling their own colour and reserve.
2v2 — Kaissa's team format: partners play one colour, alternate moves and share a team reserve. A drop also counts as a move and passes the next turn to your partner.
Bughouse uses two boards and sends captures to a partner on the other board. In Crazyhouse the reserve stays on the same board and belongs to the capturing side.
Reserves and drops
- A captured knight, bishop, rook or queen changes colour and enters your reserve. Kings cannot be captured or dropped.
- On your turn either move a piece or drop one reserve piece onto an empty square.
- Pawns may only be dropped on ranks 2–7. A pawn dropped on its starting rank can make the usual double move.
- A drop can block check, give check or deliver mate, including a pawn drop. You may never leave your king in check.
- A promoted piece retains its origin when it moves. When captured it enters the reserve as a pawn, regardless of its promoted type.
- Castling, en passant and promotion choices otherwise work normally. Dropping a rook does not restore castling rights.
See it on the board
Capture → reserve → drop
After exd5 White gains a reserve pawn. Black replies Qxd5, then White drops their pawn on e4. Black also keeps the captured pawn in their own reserve.
Defending with a drop
White is in check and the king cannot escape. N@e2 blocks the rook's line. A position is not checkmate while this drop is available.
A promoted queen returns as a pawn
The black queen on b7 was promoted. After Rxb7 White receives a reserve pawn rather than a queen, and can drop it on the next turn.
Mate from the reserve
N@f7# delivers mate from the reserve. Black has no reserve pieces and no legal defence.
Ending the game
Checkmate considers ordinary moves and every available drop. Resignation or running out of selected clock time loses the game. Stalemate and threefold repetition of the full position, including reserves, are draws. In 2v2 the partner turn order also counts. The fifty-move rule and insufficient-material draws do not apply.
Start playing
Press Play, choose a mode in the lobby and wait for people or the bot countdown. Crazyhouse defaults to no clock; a time control can be selected before starting. On your turn select a reserve piece and a highlighted square, or drag the piece onto the board. Bots understand both reserves and can drop pieces. In 2v2 the highlighted player shows whose turn it is.
Play 1v1 · Play 2v2Bughouse · 2×2