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Glossary

The words you will hear at a Bughouse board, from A to Z. Bughouse-specific terms are tagged; everything else is shared with standard chess. New to the game entirely? The Quick Start guide is the best place to begin.

Capture

Moving a piece onto a square occupied by an enemy piece, removing it. In Bughouse a captured piece never leaves the game — it goes to your partner's pocket on the other board.

Castling

A once-per-game move where the king slides two squares toward a rook and the rook hops over it. A dropped rook can never castle — it counts as having moved. See Chess Basics for the full conditions.

Check

Your king is under attack and you must deal with it immediately: move the king, block the attack, or capture the attacker. In Bughouse a drop can both give check and block one.

Checkmate

Check with no escape. In Bughouse, checkmate on either board ends the whole match — the team whose player was mated loses.

Contact checkBughouse

A check given from a square directly next to the enemy king. Feared in Bughouse because there is no square in between — it cannot be blocked by a drop, so only capturing the checker or moving the king helps.

DropBughouse

Placing a piece from your pocket onto any empty square instead of making a normal move. Drops never capture, and pawns may not be dropped on the 1st or 8th rank. The Full Rules cover every restriction.

Drop-mateBughouse

Checkmate delivered by a drop. Legal by default here, though a match can be configured to forbid it — in that case only the mating drop is rejected, and other checks by drop remain fine.

En passant

A special pawn capture of an enemy pawn that just advanced two squares past yours, allowed on the very next move only. A dropped pawn can never be captured en passant.

Exchange

A trade: you capture a piece and your opponent recaptures. In Bughouse every exchange also fills pockets on the other board, which is why "don't trade" is one of the most common partner requests.

FeedBughouse

To send pieces to a pocket through captures. Capturing feeds your partner; letting your own pieces be taken feeds your opponent's partner — expect to hear about it if you feed the enemy the exact piece that mates your teammate.

File

A vertical column of the board, labeled a through h. Rooks and queens are strongest on open files.

Flag

To run out of time — your "flag falls." Flag-fall on either board ends the whole match, and the flagged player's team loses. Playing fast to win on time is called flagging your opponent.

Fork

One piece attacking two or more enemy pieces at the same time. Dropped knights are the classic Bughouse forkers — they appear out of nowhere.

GoBughouse

A team signal meaning "play on — you don't need to wait for me." The opposite of sit.

HoldBughouse

A request to keep a piece safe: either don't trade it away so the enemy team never pockets one, or keep the one in your pocket until the right moment instead of dropping it early.

Increment

Time added to your clock after each move you make, as part of the match's time control.

Mate in handBughouse

A forced checkmate using the pieces already in your pocket (or about to arrive from your partner). With mate in hand you can ignore almost anything happening elsewhere and just deliver it.

PartnerBughouse

Your teammate on the other board. You play opposite colors, your captures land in their pocket, and you win or lose together as a team.

Pin

A piece that cannot — or should not — move because a more valuable piece sits behind it on the same line, often the king. A pinned defender is a favorite target for drops.

PocketBughouse

Your reserve of droppable pieces, also called the reserve. Everything your partner captures appears in your pocket in your color, ready to drop. The Quick Start shows how it works in play.

PremoveBughouse

Queuing your next move while it is still your opponent's turn so it plays instantly when your turn starts. It saves precious fractions of a second — but it executes even if the position has changed under you.

Promotion

A pawn reaching the last rank becomes a queen, rook, bishop, or knight. In Bughouse a promoted piece reverts to a pawn when captured — the capturer's partner receives a pawn, not the promoted piece.

Rank

A horizontal row of the board, numbered 1 through 8. Pawns may not be dropped on the 1st or 8th rank.

Sacrifice

Deliberately giving up material for an attack or positional gain. In Bughouse a sacrifice costs twice: you lose the piece and it arms the enemy partner's pocket.

SitBughouse

A team signal meaning "stop moving" — also called stalling. You sit to avoid feeding pieces while your partner is in danger, letting your own clock run instead. Since flagging loses the match, sitting is always a calculated risk.

Skewer

An attack through a valuable piece onto another piece behind it — the reverse of a pin. The valuable piece must move, and the one behind it falls.

Stalemate

Having no legal move while not in check — a draw in standard chess. It is vanishingly rare in Bughouse: with pieces in your pocket there is almost always a legal drop.

Tempo

One move's worth of time. Gaining a tempo means forcing a reply while improving your position; in Bughouse, tempo also converts directly into clock time for your team.

Time control

The clock settings for a match: starting time plus any increment or delay per move. Each board runs its own pair of clocks, and either board can decide the match on time.

TransferBughouse

The defining Bughouse rule, also called piece passing: a captured piece travels to your partner's pocket on the other board and switches to their color.

Zugzwang

A position where every move makes things worse, but you must move. It is rarer in Bughouse — a drop is usually available — but the idea still shapes endgames.