As part of a wider crackdown, police referred 10 people in Tokyo and Chiba Prefecture to prosecutors on suspicion of gambling at online casinos.

Police have around 130 others in their sights nationwide, too.

The individuals tried their luck with slot machines, roulette and other games of chance at Bitcasino, Sportsbet.io and Vera & John between April 29, 2023, and Sept. 19 this year, Tokyo’s Metropolitan Police Department said Nov. 26.

The suspects used cryptocurrencies for their bets. They all admitted to the allegations, police said.

Police said the three sites, operated overseas, can be accessed via a personal computer or smartphone.

The suspects range in age from their 20s to 60s and include a homemaker, company employees and a public servant, police said.

All suffered losses. One individual lost as much as 30 million yen ($194,000), police said.

The MPD has identified about 130 others suspected of having gambled at online casinos. It plans to act against them in conjunction with the relevant prefectural police departments.

Betting at online casinos is banned in Japan, even if sites are legally operated overseas.

On the social media platform X, many posts advertise casino websites in Japanese.

One site said customers can start playing games in seven minutes. Another said more than 4,000 games are available.

Typically, a customer needs only to register their name, address and telephone number and choose payment and withdrawal methods, such as credit cards and cryptocurrencies.

The National Police Agency said 566 people were arrested or referred to prosecutors in 73 cases related to online casinos nationwide over the past five years.

The suspects included both customers and bookmakers.

The latest case represents the first simultaneous crackdown on customers in different locations.

The results of a welfare ministry survey released in August suggested that the novel coronavirus pandemic contributed to addiction to online casinos.

A combined 19.9 percent of suspected gambling addicts said they either gambled online more frequently than before the pandemic or started gambling online.

Among other respondents, 3.6 percent chose either of the two responses.

Asked about the type of gambling that has become a problem to those unable to break the habit, 7.5 percent of suspected addicts and 11.7 percent of their family members cited online casinos.

(This article was compiled from reports by Shun Yoshimura and Daichi Itakura.)