Atomic chess is identical to regular chess with one exception. The exception regards what happens when one piece captures another piece. In regular chess the captured piece is removed from the board and the capturing piece takes its place. In atomic chess both pieces are 'killed' (i.e. removed from the board) because every capture releases an atomic explosion. In addition, this explosion extends to all 8 surrounding squares. Any pieces caught in the surrounding squares are also killed with the sole exception of pawns. Pawns are killed only when they are involved in the actual capture event in the central square. Otherwise they are unharmed and remain on the board.
Checkmate is rarely achieved in atomic chess. Instead, the death of the opposing king happens when he is caught too near an atomic explosion. Thus, both players endeavor to capture a piece adjacent to their opponent's king, igniting an atomic explosion and slaying the king.
Because White has the initiative, Black is often reduced initially to fending off crude threats of atomic death directed at his pawn at f7. If he survives, however, the tables can turn very quickly in this game of unabashed destruction.
Games rarely last any longer than five minutes. Some players find that adding their own sound effects enhances the experience.