Kozan TAKAI (1806 - 1883), a wealthy farmer and merchant who was born at Obuse in Shinshu, managed a brewery and had a wide knowledge including Yomei-gaku (neo-Confucianism based on the teachings of Wang Yangming), met Hokusai when he traveled to study at Edo, and became his disciple.
信州小布施町を生地とし造酒業を主とした豪農商にして陽明学等学問にも通じた高井鴻山（文化3年-明治16年〈1806年-1883年〉）は、江戸での遊学の折、北斎と知り合い、門下となっている。