Chinese culture had been introduced to Japan by the Three Kingdoms of Korea before the imperial Japanese embassies to China were established.
About twenty years after the deaths of Shōtoku (in A.D. 622), Soga Umako (in A.D. 626), and Empress Suiko (in A.D. 628), court intrigues over succession and the threat of a Chinese invasion led to a palace coup against the Soga oppression in A.D. 645.