However, from the fact that on the inscription itself, words such as 'tenno' (emperor) and 'togu' (crown prince), and Japanese expressions such as 'oomimi itazuki tamaishitoki' (the emperor is sick) are used, which are too early to be used for the reign of Empress Suiko, and also from the fact that the writing style had a tenor of the early Tang period; accordingly there are theories that these expressions are from the early Tang period, leaving many questions.
しかしこの銘文自体が、「天皇」、「東宮聖王」などの語や「大御身労賜時」といった日本的な表現が使用されており、推古朝では早過ぎることや、書風に初唐の趣があることから初唐代のものとする説などがあり、疑問が多い。