lastmove

The term "lastmove" in the context of chess refers to the most recent move played by either White or Black. It is a fundamental concept in understanding the progression of a chess game. When analyzing a position, identifying the lastmove is crucial for determining whose turn it is to play. This information is essential for any chess engine or player attempting to calculate future possibilities or evaluate the current state of the board. Chess notation systems, such as algebraic notation, explicitly record the lastmove made by each player. For example, in a game where White just played e4, "e4" would be the lastmove. If Black then responded with c5, "c5" would become the new lastmove. Understanding the lastmove also plays a role in certain special chess rules, like the en passant capture, which is only legal if the opponent's immediately preceding move was a two-square pawn advance from its starting rank. Therefore, "lastmove" is a simple yet vital piece of information in the game of chess.