During the transitional period leading into the Joseon dynasty some Korean buddhist painters left for Japan. Yi Su-mun (1400?–1450?) who is considered the founder of Soga school of Japan, was a boat-companion of the older priest-painter, Shubun of Shokokuji when he returned from Korea to Japan in 1424. Japanese tradition declared that Yi was so skilled after his "Catfish and Gourd" painting that Shogun Yoshimochi claimed him to be a son of the legendary Josetsu, as an adoptive honorific. Yi painted alongside and influenced the originals of Japanese zen art; and was known in Japan by his Japanese name "Ri Shubun" or "the Korean Shubun". The entire tradition of "needle points" in Japanese art began with Yi, and continued through his students, known as the Soga School, a more natural group of artists than the courtly school patronized by the Ashikaga shoguns.