Knight (chess) king); in descriptive chess notation, "Kt" is sometimes used instead, mainly in older literature. In chess problems and endgame studies, the letter "S", standing for the German name for the piece, "Springer", is often used (and in some variants of fairy chess "N" is used for the popular fairy chess piece, the nightrider). Even among sets of the standard Staunton pattern, the style of the pieces varies. The knights vary considerably. Here are some examples. The knight, along with the king and the rook, has the oldest defined movement of any chess piece, its movement being unchanged since the invention
Algebraic notation (chess) of chess is ICCF numeric notation. In recent years, the majority of correspondence games have been played on on-line servers rather than by email or post, leading to a decline in the use of ICCF numeric notation. Chess games are often stored in computer files using Portable Game Notation (PGN), which uses algebraic chess notation as well as additional markings to codify a game. As mentioned, PGN requires uppercase letter "O" to represent castling (e.g. O-O), while the FIDE Handbook uses digit zero (0-0). Though not technically a part of algebraic notation, the following are some common symbols frequently used