[Minabuchi no] Shōan was a seventh-century Confucianist and tutor of the Tenji Emperor (r. 668-671) whose many writings had entirely disappeared by modern times, according to most scholars in [Seikyō] Gondō's day. Nan'ensho, its editors asserted, was based on a manuscript by [Minabuchi] himself that had belonged to the Gondō family for generations, supplemented by a variant text recently discovered in Sendai. The publishers of this work, composed in classical Chinese, were sufficiently satisfied of its authenticity to advertise that Nan'ensho was sixty years older than the Kojiki ...

Nan'ensho purported to be a record of questions and answers between [Minabuchi] and Tenji when the latter was crown prince. It described early invasions of Korea under [Jimmu], ancient Korean-Japanese trade contracts, victories and defeats in battle, and a harmonious rural society in ancient Japan governed by cooperation and mutual aid. Although the book was said to have been written at the height of Chinese cultural influence on Japan in the seventh century, its view of the state appeared to be closer to the utopian self-rule teachings of the Chinese philosophers Mencius and [Mozi] than to the imperial Confucianism patronized in Japan at the time.

... In the case of Nan'ensho, the public at large soon also became aware of its publication because Gondō and Ozawa dedicated the edition to [Emperor Meiji] and arranged for its formal presentation to the throne through the intervention of Prince Ichijō Saneteru. The newspapers immediately debated its authenticity without reaching a consensus ...

Nothing else has been written on this subject in the postwar period.