This study examines practices relating to four dimensions of leadership development (recruitment and selection, professional learning, autonomy, and evaluation) in Japan. Initial information was drawn from prior literature and websites of the national government (e.g., national legislation, policy documents, and national statistics) and BOEs at prefectures and ordinance-designated cities (ODC) (e.g., regional legislation, standards for principals, and PD documents) by searching for such words as "principal leadership" and "professional development." Additionally, a survey on detailed information was sent to all the 47 prefectural and 20 ODC BOEs. Regional differences as well as a national trend were illuminated by triangulating a variety of sources mentioned above, while connections within and among dimensions are made clear by using legislation, policy documents and prior literature. It reveals (1) recruitment and selection overly dependent on seniority, and ambitious but unsuccessful reforms to attract private citizen principals, (2) inconsistent and undifferentiated professional learning opportunities, (3) limited principal autonomy over personnel and finance issues except for a few local governments, and (4) recent development of principal evaluation systems as separated from those for educators in general. Policymakers should carefully design policies that build the capacity for principals through a coherent, differentiated, and sustained leadership development opportunities.