Chess glossary
Chess glossary
Plain-English definitions of the chess terms that come up in Mainline, the tactics, endgame techniques, and training ideas worth knowing. Each links to a fuller entry. New here? Start with the About Mainline page.
- Fork
- A single piece attacking two or more enemy pieces at once, forcing the opponent to lose one.
- Pin
- A move that traps a piece against a more valuable piece behind it, so moving it would expose the greater loss.
- Skewer
- The reverse of a pin: a valuable piece is attacked and forced to move, exposing a lesser piece behind it.
- Discovered attack
- Moving one piece to unveil an attack from a piece behind it, creating two threats at once.
- Zwischenzug
- An "in-between" move inserted before an expected recapture, changing the outcome of an exchange.
- Zugzwang
- A position where any move a player makes worsens their position, but they're forced to move anyway. Common in endgames.
- Back-rank mate
- A checkmate delivered along the back rank by a rook or queen against a king trapped behind its own pawns.
- Removing the defender
- Capturing or deflecting the piece that guards a key square or piece, so the now-undefended target can be taken.
- Opposition
- A king-and-pawn endgame technique where placing your king directly facing the enemy king (with one square between) forces it to give ground.
- Lucena position
- A famous winning rook-endgame technique ("building a bridge") for converting a rook-and-pawn advantage.
- Gambit
- An opening where a player sacrifices material, usually a pawn, for faster development or attacking chances (e.g. the Danish Gambit, trained on Mainline).
- Repertoire
- The set of openings a player chooses to use with White and Black. Mainline builds yours around the lines you actually face.
- Spaced repetition
- A learning method that re-tests material at increasing intervals to move it into long-term memory; Mainline uses it to lock in mastered patterns.
- Blunder
- A move that significantly worsens your position, usually losing material or a winning advantage. Mainline turns your real blunders into drills.