Sub-Grades
Individual condition scores for specific aspects of a card — typically Centering, Corners, Edges, and Surface. Used by BGS and CGC but not PSA or SGC.
Sub-grades break down a card's overall grade into four components: Centering (how well the image is centered on the card), Corners (sharpness of all four corners), Edges (smoothness and integrity of card edges), and Surface (absence of scratches, staining, or print defects).
BGS popularized sub-grades and they are one of the main reasons collectors choose BGS over PSA. Sub-grades provide transparency — you can see exactly why a card received its grade and whether a specific sub-grade is pulling the overall score down.
A BGS 9.5 with sub-grades of 10/9.5/9.5/9.5 is more valuable than a BGS 9.5 with sub-grades of 9.5/9.5/9/10, because the first card was close to a BGS 10 Pristine. Savvy collectors check sub-grades before purchasing graded cards.