In 1553 he established 21 articles of Imagawa Kana Mokuroku Tsuika (expanding on the Imagawa family rules), which is bunkokuho (the law individual sengoku-daimyo enforced in their own domain) of the Imagawa territory.
天文22年（1553年）、今川氏の分国法である今川仮名目録追加21箇条の制定。