Bughouse

Bughouse — called quadriglia in Italian, and also known as Siamese or tandem chess — is chess for four players on two boards. You and a partner take on another pair, but you each play on a different board, and the pieces you capture become ammunition for your partner.

The setup

• Four players, two teams of two. Two standard chess boards, side by side.
• Partners play opposite colours: if you have White on board 1, your partner has Black on board 2 (and vice-versa).
• Teammates sit next to each other so they can hand pieces across — and talk.
• Each board has its own clock. Bughouse is almost always played fast: 3–5 minutes each.

The twist: captured pieces change boards

• When you capture a piece, you give it to your partner. It goes into their reserve (their "hand").
• Instead of making a normal move, a player may drop a reserve piece onto any empty square.
• Dropped pawns may not land on the 1st or 8th rank.
• A drop can give check — and yes, drop-mate is allowed: dropping a piece that delivers checkmate ends the game on the spot, and it is one of the most common ways bughouse games finish.
• A dropped pawn can still promote; a promoted piece reverts to a pawn when captured.

How to win

Checkmate on EITHER board wins the game for that whole team — and so does a flag fall (running out of time) on either board. You can be completely winning on your board and still lose because your partner got mated. You win and lose together.

Tactics & etiquette

• Talk constantly: "I need a knight!", "Don’t trade queens", "Sit!".
• "Sitting" means stalling your clock, waiting for your partner to feed you the exact piece you need.
• Watch both boards: a piece you trade away becomes a weapon in your opponents’ hands.
• Mating attacks are brutal — a single piece dropped next to a king can end it instantly.