However, the increasing influence from the Chinese Tang culture of the early Heian period, Emperor Kammu issued a decree to encourage the Han pronunciations of the Chinese characters on January 11, 793, which in effect forced the students learn it ("Nihongiryaku" (Abstract of Japanese History)), and on March 10, 798, students were prohibited from learning Goon, the existing pronunciations from the Southern Dynasty in China were prohibited and were instructed to learn the Han pronunciations of the Chinese characters ("Koninkyakusho" (Regulations in Konin period)).
それでも唐の文化の影響が強まった平安時代初期の延暦11年11月20日(旧暦)（793年1月7日）、桓武天皇が漢音奨励の勅を出して学生には漢音の学習が義務づけられ（『日本紀略』）、続いて延暦17年2月14日(旧暦)（798年3月6日）には学生に従来から日本に存在する南朝(中国)系の呉音を禁じて漢音での発音が義務付けられた（『弘仁格抄』）。