Chess Glossary

Blunder A very bad move that significantly worsens your position. Castling A king-and-rook move that improves king safety. Check A direct attack on the king that must be answered immediately. Checkmate The king is in check and cannot escape — the game ends. Development Bringing your pieces out to active squares in the opening. Discovered Attack Moving one piece unveils an attack from another behind it. En Passant A special pawn capture of a pawn that just advanced two squares. Endgame The final phase, with few pieces left on the board. Fianchetto Developing a bishop to a long diagonal via b2, g2, b7 or g7. Fork A single piece attacking two or more enemy pieces at once. Gambit Sacrificing material (usually a pawn) early for activity. Initiative The ability to make threats that force the opponent to respond. Isolated Pawn A pawn with no friendly pawns on adjacent files. Opening The first phase of a game, governed by development principles. Opposition A king-and-pawn endgame technique of facing kings. Outpost A square (often for a knight) that can't be attacked by enemy pawns. Passed Pawn A pawn with no enemy pawns able to stop it promoting. Pawn Structure The arrangement of pawns, which shapes a game's plans. Pin A piece that cannot move because a more valuable piece sits behind it. Promotion A pawn reaching the last rank becomes a stronger piece. Sacrifice Giving up material for a greater positional or attacking gain. Skewer Like a pin in reverse: a valuable piece is forced to move, exposing one behind it. Stalemate No legal move and not in check — the game is a draw. Tactic A short forcing sequence that wins material or mates. Tempo A single unit of time — one move. Zugzwang A position where any move you make worsens your position. Zwischenzug An in-between move inserted before an expected reply.