Nisshimura & Asahi have created this useful presentation on Lessons Learned from Recent JapaneseM&A Contract Interpretation Cases, which covers recent legal history in this area and the following topics:
Emancipation of Japanese M&A Contract Drafting
Entire Agreement Clause
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.