For four years a hedge fund urged one of Japan's oldest companies to raise its dividend, and each time the answer in public was no.

Behind the scenes, something else was happening. Though it lost every proxy fight, the Children's Investment Fund claims a list of wins. Japan Tobacco Inc. boosted its payout ratio and said it would exit its beverage businesses. The state sold some of its stake. Since May 2011, the month the fund says it first met with management, the shares surged more than 180 percent.

The Children's Investment Fund versus Japan Tobacco shows activism can pay in a country where many scoffed at the suggestion. It's a case study that matters as Japan Inc. prepares for more barbarians at its gate.