The country's corporate boards used to be like a closed village, typically consisting of executives who climbed the corporate ladder within the company and lacking views from outside directors that could be critical for management strategy.

But during the reign of outgoing Prime Minister Shinzo Abe, companies have opened up more to outside scrutiny, thanks to Abenomics’ key policy of prodding companies to strengthen corporate governance and boosting the profitability of firms as a result.

“Compared with the past attempts to enhance corporate governance, the Abe administration’s reform was far more specific and moved things forward” by introducing new guidelines and rules, said Takaaki Wakasugi, the head of the Japan Corporate Governance Research Institute.