Descriptive notation abbreviated to the first letter of its name: K for king, Q for queen, R for rook, B for bishop, P for pawn. Knight begins with the same letter as king, so it is abbreviated to either "Kt" (used in older chess literature) or "N". "N" is used in this article. In 1944 "Chess Review" received many letters debating the change from Kt to N . In descriptive notation each square has two names, depending on Black's or White's viewpoint. Each is given a name corresponding with the piece that occupies the first at the start of the game. Thus
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