Blackrock new proxy voting guidelines for US securitiesadd considerable detail. With the promulgation of the new corporate governance code, it will be interesting to see if the firm comes up with guidelines for Japan that have a similar level of concreteness.
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.