Those who are higher than Kugyo (high court noble, Sanmi (Third Rank)) can wear shiraaya (white woven fabric) and those who are more than daibu (master, goi (Fifth Rank)) can wear shiro kosode (a kind of white underwear).
白綾は公卿（＝三位）以上、白小袖は大夫（＝五位）以上に許す。