Japanese officials, business leaders, and scholars have begun a wide-ranging review of corporate governance there, which could lead to significant changes in corporate law and governance requirements for public companies.

Two groups—one run by the Financial Services Agency, the other by the Ministry of Economy, Trade and Industry—have been working on parallel tracks for several months pondering possible improvements to Japanese governance. Most notably, both have been discussing whether to mandate the presence of outside directors on the boards of public companies, and how to define outside directors in the first place.

Kazuhito Ikeo, a finance professor at Keio University, chairs ...