The Smart Game Format (SGF) is a file format used for storing records of board games. Go is the game that is most commonly represented in this format and is the default. SGF was originally created under a different name by Anders Kierulf for his SmartGO program.

The main purposes of SGF are to store records of played games and to provide features for storing annotated and analyzed games (e.g. board markup, variations). It is a text-only, tree-based format.

Most Internet Go servers and Go software from 1990 support this format.

An SGF file is composed of pairs of properties and property values, each of which describes a feature of the game. A partial list of properties appears below.

There is no strict checking of the contents of these tags, so it is possible to put any text into the result tag for example.

Variations are nested in brackets, and also usually assigned letters. The first branch (variation A) is the main branch. This notation stems from Newick format.

The first letter designates the column (left to right), the second the row (top to bottom). The upper left part of the board is used for smaller boards, e.g. letters "a"-"m" for 13*13.

The author intentionally broke with the tradition of labeling moves (and points) with letters "A"-"T" (excluding "i") and numbers 1-19. Two lower-case letters in the range "a"-"s" were used instead, for reasons of simplicity and compactness.