There are various ways to lose a game of chess. Some types of loss are common to all chess games (e.g., checkmate), but there are some that depend on the tournament’s official rules. The main ways to lose at chess include:

  • Checkmate: You lose the game if you are checkmated on the board.
  • Time forfeit: You ran out of time on your chess clock.
  • Resignation: You voluntarily give up and concede defeat.
  • King capture: Some rapid play or lightning games allow the King to be captured. Other tournaments (usually longer games) require that illegal moves that leave the King in check have to be undone and some other legal move played instead.
  • Adjudication: An unfinished game can be assessed by an adjudicator, who may declare it a win/loss, or a draw.

Some of the more obscure ways to lose at chess include:

  • Illegal Move Loss: In some tournaments where king captures are a win, if you make an illegal move of any other kind, your opponent can claim a win. Leaving the King in check is not the only type of illegal move.
  • Late Arrival Forfeit: you failed to arrive at a tournament game within the “grace period”.
  • Mobile Phone Forfeit: if your mobile phone rings during a game, you are supposed to forfeit immediately. It’s a bit unclear whether a “ping” from a text is a loss?
  • Electronic Device Forfeit: the newer rules often actually disallow having any type of mobile phone or electronic device on your person while playing.
  • Official Penalty: the tournament referee can impose a loss as a penalty for a variety of reasons (e.g. electronic device forfeit, failure to record the game on a scoresheet, cheating, rule violations, etc.). In some cases, a warning may be issued rather than an immediate penalty.

Note that stalemate is not actually a loss, but is a draw. Similarly, perpetual check is a draw, not a loss.

A loss in a chess tournament usually counts as 0 points. A win is 1 point, and a draw is a half point (for both players).