In the batsu he wrote that the famous 'Fushinjo' (the letters Kukai wrote to Saicho) in To-ji Temple and 'Kyujosho' were the best in Kukai's calligraphy, seeking the origin in ASANO no Nakai during Nara period, and furthermore Nakai originated from the copying of a sutra during Tang Dynasty.
この跋には、空海の書は東寺にある有名な「風信帖」とこの「急就章」がもっともよいとし、その源流を奈良時代の魚養に求め、さらに魚養は唐写経に由来すると述べている。