During the latter half of Heian period, the court nobles called the garment with big sleeve openings 'Oosode' and the garment with small sleeve openings 'Kosode' in contrast to 'Oosode.'
平安時代後期に公家は、袖口が大きい服を大袖と呼び、大袖に対して袖口が小さい服を小袖と呼んでいた。