If this 83-year-old billionaire is right, one of the most important lessons of business school is pretty much wrong.

All that stuff about focusing on shareholders, forget it, says Kazuo Inamori, entrepreneur, management guru and Buddhist priest. Spend your time making staff happy instead. He has used this philosophy to establish electronics giant Kyocera Corp. more than five decades ago, create the $64 billion phone carrier now known as KDDI Corp., and rescue Japan Airlines Co. from its 2010 bankruptcy.

From Kyocera's headquarters overlooking the hills and temples of the ancient capital of Kyoto, Inamori expresses doubts about Western capitalist ways. His views are a reminder that many bastions of Japanese business do not buy into Prime Minister Shinzo Abe's plans to make companies more devoted to shareholders.