X-FEN [SEP] based on
X-FEN
X-FEN is an extension of Forsyth-Edwards Notation (FEN).
The traditional Forsyth-Edwards Notation is not sufficient to represent all possible positions in 8×8 Chess960 (aka Fischer Random Chess) or 10×8 Capablanca Random Chess (CRC). Consequently, an extension of FEN was needed, with the requirement of being fully backward compatible. X-FEN (formerly FRC-FEN), introduced by Reinhard Scharnagl in 2003, accomplishes this.
X-FEN definition.
X-FEN
is based on traditional FEN. It differs only in the way that castling and "en passant" tags are used. Moreover, 10×8 positions which use princess (knight+bishop) and empress (knight+rook) compound pieces are supported.
X-FEN definition X-FEN inside of PGN.
Games are translated into PGN format (Portable Game Notation). Each game's starting position must be stored in the PGN for Chess960 and Capablanca Random Chess(CRC) (but not for traditional chess). Storing the starting position is accomplished with