FEN — Forsyth–Edwards Notation

FEN captures an entire chess position in a single line of text. It's how positions are shared in articles, puzzles, and between programs.

The six fields

A FEN has six space-separated fields. The starting position is:

rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1

1 — Piece placement

Read rank 8 to rank 1, each separated by /. Uppercase letters are White pieces (KQRBNP), lowercase are Black (kqrbnp), and digits count consecutive empty squares. So 8 is an empty rank.

2 — Side to move

w means White moves next, b means Black.

3–4 — Castling & en passant

Castling availability uses K/Q (White) and k/q (Black), or - if none. The en-passant field names the target square (e.g. e3) or -.

5–6 — Halfmove clock & move number

The halfmove clock counts plies since the last capture or pawn move (for the fifty-move rule). The last field is the full move number, starting at 1.

Try a FEN

Paste any FEN into the FEN viewer & editor to see the position, or build one and copy the FEN back out.