Christina Ahmadjian, an academic and expert in corporate governance, sits on the boards of several Japanese companies, including Mitsubishi Heavy Industries and Japan Exchange Group, the holding company that oversees the Tokyo Stock Exchange. Often the lone foreigner and only woman in the room, Ahmadjian relishes playing gadfly and applying her research to real-life situations.

"Just my presence makes a difference," she explains, "as these company presidents are forced to answer my questions, and I have a voice to ask: 'What effect will this decision make on your shareholders? How does this affect other stakeholders?' "

Ahmadjian welcomes recent moves to open up corporate governance in Japan, buoyed by support from Prime Minister Shinzo Abe's government, which has introduced a range of measures to shake up the membership of Japan Inc.'s notoriously insular company boards.