Forsyth notation

Forsyth notation began as a concise way to turn a diagram into text. David Forsyth published his proposal in 1883. Historical usage developed variants and was never completely standardized.

Its central idea survives in FEN, short for Forsyth-Edwards Notation. In the modern piece-placement field, the board is read from the eighth rank to the first. Slashes separate ranks, letters represent pieces, and a digit gives the number of consecutive empty squares. Uppercase letters represent White's pieces and lowercase letters Black's.

That field describes where the pieces are, but it is not enough to reconstruct the full legal state. A complete FEN record also gives the side to move, whether either side still has castling rights, the target square for a possible en passant pawn capture, and two move counters.

Forsyth is therefore a position notation, not a move notation. It also differs from the GBR code, which classifies the material present without locating each piece on a square.