Space-advantage annotation symbol

In chess, space is the useful territory a side controls, often through advanced pawns that restrict opposing pieces. The circles ○ and ◯ are visual variants of the mark used to show that one player has more space and usually more squares available for arranging pieces.

In Scid's NAG table, one circle means a slight space advantage, two a moderate advantage, and three a decisive one. NAG means Numeric Annotation Glyph, a numeric code stored with the game. White and Black have different codes even when the visible glyph is identical, so the program or context identifies the favored side.

More space does not mean having more material, meaning more pieces or pawns, or launching an immediate attack. It can also leave advanced pawns as targets. The mark summarizes a territorial advantage, while the pawn-count-advantage symbol describes a different material comparison.