What is FEN (Forsyth-Edwards Notation) in chess?
A compact text string that describes the exact state of a chess position.
FEN encodes piece positions, the side to move, castling rights, and en passant options in a single line of text. Engines, websites, and apps use FEN to set up any position instantly without replaying all the moves.
Spot fen (forsyth-edwards notation) in your own games
Free. Chess2EZ finds the patterns you keep missing and explains each in plain English.
Analyze my games →More chess terms
- MistakeA move that significantly worsens your position, but is less severe than a blunder.
- InaccuracyA move that is slightly suboptimal but does not throw away the game.
- BrilliancyA spectacular, usually unexpected sacrifice or combination that is objectively sound and aesthetically striking.
- Elo ratingA number that estimates a player's strength from their results.
- Time controlThe amount of time each player has to complete their moves.
- Bullet chessAn ultra-fast time control with one or two minutes for the entire game.