Competitive gaming in Japan has found a champion: hedge fund boss Seth Fischer.

The chief investment officer of Hong Kong-based Oasis Management Co., which owns more than $1 billion in Japanese securities, said esports is now among his top five investment themes for Japan. He has started buying stocks of game publishers like Capcom Co. and Square Enix Holdings Co., looking to cash in as the country that practically invented video games begins a long-delayed embrace of professional gaming.

Fischer is among a few early believers that competitive gaming can become big business in Japan.