Yoshifusa focused on the development of the legal system and completed establishment of the Jogan Kyakushiki Code (Regulations and Procedures of the Jogan Era), with the "kyaku" being promulgated in 869, and the "shiki" in 871.
法制の整備に力を入れて、「貞観格式」を完成させた（格は貞観11年（869年）、式は貞観13年（871年）に公布）。