However, Hiromichi MORI states that Nihonshoki Vol. 22 containing 'Suikoki' belongs to the βgroup, which is described in the Japanese phonetic system (i.e., written by the Japanese people including monks who had studied in Silla), and not the α group, which is described in the Chinese phonetic system (i.e., written by Chinese people visiting Japan).
しかし、森博達は「推古紀」を含む日本書紀巻22は中国音による表記の巻（渡来唐人の述作）α群ではなく、日本音の表記の巻（日本人新羅留学僧らの述作）β群に属するとする。