Itsuun first learned nanga painting from Yushi ISHIZAKI, a karae-mekiki (one of the services of Nagasaki Magistrate's Office in charge of evaluation of artistic articles exported from China and sketching of traded items, birds and animals) and mastered the technique of nanga from Chinese painters who came to Japan, Jiang Jiapu and Zhang Quigu.
画は、はじめ唐絵目利の石崎融思に学び、来舶清人の江稼圃・張秋谷からは南画の技法を修めた。