The description within the diary of FUJIWARA no Teika (Sadaie), "Meigetsuki" (the entry dated December 10, 1203 (old calendar)) was supposedly the first place where the word, 'Kaisho' was mentioned.
藤原定家の日記、『明月記』（建仁1203年十二月十日条）にある記述は、「会所」の初見とされる。