At the same time, he insisted that every historical finding had to be closely investigated using excavated articles and any historical story or description should not be accepted without such a step even if it was seen in the Kojiki (Record of Ancient Matters) and the Nihonshoki (Chronicles of Japan); additionally, he wrote a book called "Shokohatsu" (Impulsive Remarks), in which the period of Emperor Jinmu's reign was moved back 600 years and the existence of jindaimoji (ancient Japanese characters which were believed to have been used before kanji characters were brought to Japan) was denied.
だが、その一方で発掘された出土品などを吟味して厳密な考証の必要を唱えて記紀の記述と言えども無条件でこれを支持すべきではないと主張し、神武天皇の在位を600年繰り下げて神代文字の存在を否定した『衝口発』を著した。