As Japan's population ages and slowly declines, bring in the robots and foreigners.

That is the view of Atsuto Sawakami, whose $2.6 billion eponymous stock fund beat the Topix index in 12 of the past 15 years. With pensioners holding most of the nation's wealth and swelling in number, his fund will profit by buying shares in developers of assistive limbs and other companies that target elderly consumers, the 68-year-old said.

Policy under Prime Minister Shinzo Abe is being shaped by an awareness that the nation's citizens are the oldest in the world. The government is doing everything from promoting greater female participation in the workforce to taking small steps toward welcoming more overseas workers in a nation where foreign residents make up less than 2 percent of the population. While Sawakami says he is for selective opening of the border, he is betting on the machines.