FEN is based on a system developed by Scottish newspaper journalist David Forsyth.
His system became popular in the 19th century, then Steven J. Edwards extended it to support its use by computers.
FEN is defined[2] in the "Portable Game Notation Specification and Implementation Guide".
A FEN record desition, all in one text line and using only the ASCII character set.
The solution implemented by chess engines like Shredder and Fritz_9 is to use the letters of the columns on which the rooks began the game.