Three-check chess is a chess variant in which the winner is the first player to check their opponent three times. Anatoly Karpov is said to excel in this variant.
The game is more tactical than standard chess: sacrifices are common and the opening can be filled with traps. Two checks constitutes a big advantage and may be worth much material in the evaluation of a position. The game rarely reaches the endgame and is usually decided before queens are traded.
Example game
1. e4 e6 2. d4??
This typical opening in standard chess immediately loses in Three-check chess.2... Bb4+
First check.3. c3 Bxc3+!
Second check.4. Nxc3 Qh4! 0–1
White resigned. There is no way to prevent a third check by Qxf2+ or Qxe4+.References
Three-check chess Wikipedia(Text) CC BY-SA