Sham sacrifice

A sham sacrifice is an offer of material, meaning pawns or pieces, whose favorable outcome can be calculated concretely. A player allows a piece to be captured, but a forced continuation with tightly restricted replies recovers the material, wins more, delivers checkmate, meaning the attacked king has no legal answer, or secures a result such as a draw, a game with no winner. The term pseudo-sacrifice is also used.

Sham does not mean that the move is fraudulent or bad. It means that the initial cost is neutralized by the result of the combination, a calculated sequence of connected moves. A real material deficit may exist for several moves, but the opponent lacks enough freedom to convert it into a benefit. Checks, captures, and threats restrict the replies until the intended outcome is reached.

The main sign is that the final benefit received in return can be calculated concretely rather than resting only on future pressure. The important replies are restricted, and the sequence ends in checkmate, recovered or additional pawns or pieces, a repeating series of checks that leads to a draw, usually through repetition of the position, or stalemate, where the player to move is not in check but has no legal move.

This distinction is historical, and its boundaries are not uniform. In one classic classification, even a category called positional sacrifice belongs among sham sacrifices when the material is forcibly recovered with an improved position. In modern usage, positional sacrifice usually means a lasting investment without immediate recovery. The author's definition therefore matters.