Zugzwang

In the game of chess, a player is required when it is his or her turn. Sometimes a player would prefer to pass, but the rules do not permit it. This compulsion to move in a bad position is called zugzwang.

The player to move in this position will lose a pawn. Although this position is an example of zugzwang, it is not fatal. The loss of a pawn in this position does not mean the loss of the game.

In the next position, the player to move loses a pawn and the game.

In the third game of their match during the First American Chess Congress, 1857, Paul Morphy reached this position with Black against James Thompson.

Black to move

1...a1N+ wins easily. I tested this idea against Stockfish this morning and had no problems winning in a few minutes. However, even stronger would be 1...Bc3 and Morphy's 1...Ka3. Both moves place White in zugzwang.