Based on this fuku-shoji, the torii-shoji (kamoi-shoji) was devised to move in two directions by drawing on the two grooves of kamoi and threshold, and it led to the original form of present day 'fusuma' and was called fusuma-shoji (衾障子 or 襖障子).
この副障子を、鴨居と敷居という二本の溝を設けて、引き違いに動くように工夫したのが鳥居障子（鴨居障子）で、今日の「ふすま」の原型となったもので、衾障子・襖障子と呼ばれた。