With respect to ginjo and daiginjo, the problem is that not only the portion to be scraped off is large, but also the object becomes smaller and requires special attention, the time needed for rice polishing sometimes exceeds two full days.
吟醸、大吟醸となると、削りこむ部分が大きいだけでなく、そのぶん対象物が小さくなって神経も使うので、精米に要する時間は丸二日を超えることもある。