Research suggesting Japanese companies can benefit from a high ratio of outside directors and outside auditors.
http://bdti.mastertree.jp/f/s6eao91f
The Board Director Training Institute (BDTI) is a "public interest" nonprofit in Japan dedicated to training about directorship, corporate governance, and related management techniques. It is certified by the Japanese government to conduct these activities as a regulated nonprofit. Read a summary about BDTI here, and see a menu of its services for both corporations and investors here.