bughouse, a four-player chess variant in which the action is so frenetic that the game is named after an old slang term for insane.
In bughouse, two chessboards are set up next to each other. Players work in teams of two, with the first teammate playing white on one board and the second playing black on the other. The rule that makes bughouse uniquely crazy is that when players capture a piece, they pass it to their partner on the other board. Each player accumulates those pieces, and on any turn can “drop” a piece from his or her “hand” onto any empty square on the board. The match ends whenever one player wins his game, earning a win for the team.
A piece can be dropped to give check, or even checkmate, so the end of the game can arrive abruptly for players who aren’t paying attention to their opponents’ off-board pieces. Players aren’t allowed to hide pieces, but they can talk to their partner during games. A player who could deliver checkmate if only she had a knight in her hand might shout “trade for a knight”—or she might whisper it. In bughouse, time is of the essence: Each board has its own chess clock, which is placed on the outside facing inward so that all four players can see both clocks. Usually, each player gets just five minutes of playing time for the entire game.
In one post-Sinquefield bughouse match, world champion Magnus Carlsen paired up with No. 9-ranked Maxime Vachier-Lagrave against the duo of top U.S. player Fabiano Caruana (world No. 3) and Levon Aronian, the longtime world No. 2. Mr. Caruana held off the world champion on his board, but Mr. Aronian’s king was overwhelmed by a swarm of Mr. Vachier-Lagrave’s airborne pieces.
For some players, bughouse can verge on addiction. Children love the fast pace and the possibility of rescuing a hopeless position by parachuting new pieces onto the board in a sneak attack.
Grandmaster and chess coach Joel Benjamin points out that because the empty squares on the board are so critical in bughouse—they are the only places new pieces may be dropped—the variant may help players start to think more about where pieces could go and less about where they already are, a skill that can be useful in normal chess. Indeed, some research on expert chess players suggests that they pay more attention to empty space than amateurs do.
Bughouse also has detractors, mainly among chess teachers who find that it encourages children to play too fast and to focus on superficial tactics and lightning attacks at the expense of patient, strategic thinking. International master David Goodman tells his younger classes that bughouse is a fun way to unwind after a period of studying or playing standard chess, but a bad way to prepare for a serious competition.
The joy of bughouse comes from the way it magnifies the exciting, tactical aspects of chess, while adding a completely new one: teamwork. But if you are serious about the traditional game, this frenetic four-player variant is perhaps best played in moderation.