Smith notation

Smith notation, designed by Warren D. Smith and used on the Internet Chess Club server, begins with four characters: the origin square followed by the destination square. Each square consists of a file letter from a to h and a rank number from 1 to 8.

It may then append an indicator for the captured piece: p for pawn, n for knight, b for bishop, r for rook, q for queen, and k for king. E identifies en passant, the special capture of a pawn that has just advanced two squares. The letters c or C can signal castling, the combined king-and-rook move. A promotion adds the chosen piece at the end.

Recording what disappeared makes the sequence reversible. Software can undo a move without separately retaining the entire previous position. That was a practical advantage for servers and chess programs.

On a quiet move, Smith can resemble UCI move notation because both begin with origin and destination. Captures and special cases reveal the difference: Smith can append the captured piece, while UCI does not.