It is said that the oldest theory of calligraphy in Japan is found in the "Japanese school of calligraphy, Yakaku Teikinsho" (calligraphy manual) written by FUJIWARA no Koreyuki described during the late Heian period (before 1177).
日本最古の書論は、平安時代後期（1177年以前）に著された藤原伊行の『日本の書流夜鶴庭訓抄』（やかくていきんしょう）とされる。