Berserk

Berserk is a rule specific to Lichess Arena tournaments, an online format in which players play repeated games during a fixed tournament period and score points. It is not a general law of chess. When a player activates Berserk at the start of a game, they accept a voluntary time disadvantage: their initial clock is cut in half. If they win, they receive one additional point toward the tournament standings.

In time controls with increment, meaning time added after each move, going Berserk normally removes the increment. In notation such as 3+2, the first number is the initial minutes and the second is the seconds added after each move. Lichess makes an exception for 1+2, which becomes 1+0. Berserk is unavailable when the initial time is zero, such as 0+1 or 0+2, and the extra point is awarded only if at least seven moves are played.

The choice changes the tradeoff between clock time and tournament score. A player can earn one additional point for a qualifying win, but has far less time to think and execute moves. That makes speed tools such as a premove more relevant and increases the danger of losing by time. A mouse slip can also be more costly when there is little clock time available to recover.