Different languages have different names for the chess pieces, and therefore use different letters to represent the pieces. This can cause confusion when using either Algebraic Chess Notation or Descriptive Chess Notation. ICCF Numeric Notation addresses this problem. The ICCF is the International Correspondence Chess Federation, and ICCF Numeric Notation is the official chess game notation for all International Correspondence Chess Federation games.
In Numeric Notation, all the squares are identified by a symbol that resembles a two-digit number. The first digit does not represent tens; it identifies the file; and the second digit identifies the rank. The file closest to white's left hand is labeled 1; the file closest to black's left hand is labeled 8. The rank closest to white is labeled 1; the rank closest to black is labeled 8.
Here is a chessboard (as seen from white's perspective) with every square labeled:
A move is recorded by combining two of these two-digit coordinates. For example: The move that would be written e4 in Algebraic Chess Notation and written P-K4 in Descriptive Chess Notation would be written 5254 in Numeric Notation, because the pawn starts from the square on the 5th file and 2nd rank, and moves to the square on the 5th file and 4th rank. Numeric Notation does not mark the type of the piece nor captures.
Except for pawn promotion, all moves consist of only four digits. In pawn promotion, a fifth digit is be added to indicate the piece chosen: "1" for queen, "2" for rook, "3" for bishop, and "4" for knight. For instance, in the case of a pawn on f7 moving to f8 and promoting to a rook, the move would be recorded as 67682.
Because the ending rank is always "8" for White and "1" for Black, the move would be completely specified even if this information were omitted. Therefore some people use a four-digit notation where the ending rank is replaced by the piece chosen. For example: 6762 instead of 67682. However, this is non-standard and discouraged.