Apparently from the description of the section of the year 929 in "Nihongi Ryaku," that is, 'the overdrawn image of Kenjo sage on the shoji of Shishinden,' apparently the date of the appearance of 'Shoji-to,' that is, Fusuma, which was set at the same time of 'Kenjo no shoji,' was from 901 to 914.
『日本紀略』延長(元号)七年（929年）の条の、「紫宸殿障子を賢聖像に改書せしむ。」の記述から、「賢聖の障子」と、同時に立てた「障子戸」すなわちふすま建具の誕生の年代は、延喜年間（901～914年）であると推測される。