17th June 2025 – (Tokyo) A man from Hong Kong used his own “winning algorithm” to gamble in Japan and win billions of yen, taking advantage of special tax rules for non-residents that kept him out of legal trouble. Japanese news reports say this individual designed a unique computer program more than ten years ago. He brought in two helpers, Tani Tsuyoshi and Tokunaka Tōryō, to help with the job. These two used the names of 60 friends and family to set up betting accounts and made over 100 bets for every competition.

During 2019 and 2021, they reportedly made profits over ¥6.1 billion (around HK$33 million) by betting on horse races, local sports, and boat races. However, ¥2.6 billion (roughly HK$14 million) of this income was not reported for taxes, and because of this, Tokyo tax officers filed charges against them based on Japan’s income tax regulations. One of the men, Tani, was once the boss of a J3 football club management company, while Tokunaka was a top manager in a restaurant business. Later, they corrected their tax documents and paid what they owed. They apologised and shared, “We deeply regret the inconvenience caused.”
Hong Kong Mastermind Escapes Charges in Billion-Yen Japanese Gambling Scheme

The main person from Hong Kong still faces no charges, because Japanese tax rules do not apply to his earnings. According to reports, he kept 90% of the money and made billions of yen, leaving just 10% for his assistants. Their advanced setup, using an automatic computer system, allowed them to buy many betting slips online, sometimes reaching ¥2 billion (about HK$109 million) in monthly bets. Although they saw steady profits each month, the project broke down after a 2024 probe by Japan’s National Tax Agency spotted suspicious patterns in the assistants’ reports.
Japanese officials have not taken more steps against the Hong Kong mastermind, who is still free and enjoying the benefits of his expertly built gambling system.