How do I decode Japanese auction grades?

Standard grades: S = near showroom condition, 6 = very minor age-related marks, 5 = some small scratches or dents, 4.5 = clean with minor cosmetic issues, 4 = presentable with visible minor blemishes, 3.5 = moderate wear for age, 3 = heavy wear or light accident repair, 2 = significant issues, 1 = rough/project car. RA = reconditioned after accident (repaired but history disclosed). R = accident history, A = flood history. Grade 4 and above is the usual import target range.