Beirut chess

Beirut chess is a chess variant created by games designer Jim Winslow in 1992 that adds a single hidden element to the standard rules, board, and pieces of chess. Before play begins, each of the two players secretly marks one of their own pieces, other than the king, as a bomb carrier known only to that player. On any turn, instead of making a normal move, a player may declare Boom and detonate their bomb, which destroys the carrier itself along with every piece of either color adjacent to it at that moment. This introduces a second way to win alongside conventional checkmate: a player who manages to blow up the opposing king wins outright, regardless of the position of the other pieces on the board. Because captured pieces are never revealed to show whether they were the bomb carrier, both players must play under genuine uncertainty about where the danger is hidden until someone actually calls Boom, giving otherwise familiar chess openings and middlegames an added layer of psychological bluffing.