As Ippei Mizuhara prepares for prison, report suggests illegal sports betting in Japan has been surging
Nearly three months after his initial reporting date for crimes related to sports betting, Ippei Mizuhara is to surrender to federal authorities in June to begin a 57-month prison sentence.
Mizuhara, the disgraced former interpreter for Shohei Ohtani, is something of a pariah in Japan, where the Dodgers baseball star is viewed as a national hero. In February, Mizuhara received a lengthy sentence in connection with embezzling at least $17 million from Ohtani to feed his gambling habit. Born in Tomakomai, a port city on Japan’s second-largest island, Mizuhara may face deportation from the US following his prison stay.
Back in Japan, where baseball is the national pastime, the rate of illegal sports gambling apparently has been soaring. Last year, citizens of Japan placed approximately ¥6.45 trillion ($44.6 billion) in overseas sports wagers even though the sites are illegal, according to a report from the nation’s Council for Sports Ecosystem Promotion. While the market has grown considerably, arrests for gambling-related offences are still minimal, according to the CSEP, which on 14 May published findings of a comprehensive investigation.
The rapid growth in sports betting in Japan shows little signs of abating. Of the vast amounts wagered offshore, approximately ¥1 trillion consists of bets involving domestic sports in Japan, the investigation found. That huge volume raises questions about sports gambling habits in Asia’s third-richest country.
A black eye for Japanese baseball
The report was issued several weeks after two members of the Yomiuri Giants were referred to prosecutors for allegedly gambling on illegal online casino sites.
The two players, Luis Okoye and Daiki Masuda, lost millions of yen on online games such as baccarat and blackjack. Okoye, a nine-year veteran, has 14 career home runs and a batting average of .226 since joining the Nippon Professional Baseball league in 2016. The outfielder wagered about ¥7 million on online casino games, producing a negative balance of around ¥4.5 million, according to Mainichi Shimbun, the nation’s largest daily newspaper.
Amid a league investigation, the NPB accused 14 players across seven teams of engaging in illegal gambling in February.
Reminders of the ‘Black Mist’ scandal
The Yomiuri Giants garnered headlines in 2015 when several players admitted to betting on baseball. According to the club, pitcher Shoki Kasahara wagered on 10 pro baseball games, while also betting on baseball at high school level.
The team also accused another pitcher at the time, Ryuya Matsumoto, of wagering on at least 10 games over a four-month period. While both pitchers admitted to wagering on baseball, they were not accused of betting on games involving their own team. A third player, Satoshi Fukuda, also admitted to wagering on high school games.
The trio also admitted to betting on MLB games in the US, according to The Japan Times. While no evidence emerged that the players engaged in match-fixing, the Times reported that the probe examined possible links to organised crime. The gambling violations took place nearly 50 years after the “Black Mist scandal“, in which several Japanese players accepted money from the famed Yakuza syndicate to fix a series of games.
Illegal markets dwarf sports lottery betting
Today, there are clear signs that Japanese bettors are wagering heavily on domestic baseball on offshore sites.
Of all wagers, domestic baseball led the way with a 2024 handle of ¥528.1 billion, according to the CSEP report. The amount dwarfed soccer, the next highest at ¥333.4 billion, and basketball with ¥86.9 billion. Tennis ranked fourth, followed by a pair of niche sports in volleyball and rugby.
While horse racing is enormously popular in Japan, betting on most sports is heavily restricted.
Sports wagering in Japan is available legally on a limited basis through a government-run sports lottery. The options are sparse, with only minor sports such as motorboat racing and cycling available. Consequently, Japanese bettors wagered ¥133.6 billion on sports lotteries in fiscal year 2024, approximately 48 times less than the amount reportedly wagered offshore.
In soccer alone, Japanese bettors wagered trillions of yen.
Unprecedented wagering patterns by Ippei
The son of a chef, Mizuhara moved to Los Angeles as a young boy in 1991. He played goalkeeper on a varsity soccer team at Diamond Bar High School before returning to Japan to serve as an interpreter for the Hokkaido Nippon-Ham Fighters.
There, he met Ohtani, a teenage prodigy for the NPB team. Besides working as Ohtani’s interpreter, Mizuhara became a close confidant of the Japanese star, serving as his catcher in bullpen sessions, preparing lavish meals and forging a bond through frequent video game battles. Mizuhara followed Ohtani to the Los Angeles Angels in 2018.
In California, Mizuhara engaged in rampant betting patterns of extremely high wagers on the illegal market. Over a 37-month period, he placed approximately 19,000 wagers with an enterprise run by illegal bookmaker Matt Bowyer. Mizuhara incurred losses so severe that he had a net balance of negative $40.2 million when he severed his relationship with Bowyer.
His relationship with Ohtani came to a head in March 2024 when reports surfaced that Mizuhara wagered heavily on sports. The interpreter initially told ESPN that Ohtani had knowledge of his betting activity, but he later recanted the story.
Mizuhara had impersonated Ohtani numerous times in calls with bank officials to gain approval for six-figure wire transfers that went to Bowyer’s operation. Ruled a victim of massive theft by Major League Baseball, Ohtani has been cleared of all wrongdoing.
Mizuhara is now scheduled to surrender to federal prison authorities by 16 June.
The reaction on Japanese soil
A three-time MVP honoured in both the American and National League, Ohtani has ostensibly become the Japanese version of Babe Ruth in his native country. Returning home for the Tokyo Series in March, Ohtani crushed a 99mph fastball 389 feet for a solo home run.
Lauding Ohtani for blocking out the pressure of playing before a rabid home crowd, Dodgers manager Dave Roberts likened the two-way player to a superhero.
Ohtani has also placed the gambling scandal squarely in the rear view mirror. Days after reports surfaced on Mizuhara’s betting habits, Ohtani denied placing any wagers on baseball or on sports in general.
He went on to produce a record year in 2024 when he became the first player in MLB history to notch 50 home runs and 50 stolen bases in the same season. Last fall, he added three dingers in the postseason, en route to the first World Series title in his illustrious career.
Mizuhara, meanwhile, has received strident criticism in Japan for bringing Ohtani into disrepute. Taro Abe, a reporter who covers Ohtani for Japanese newspaper Chunichi Shimbum, told the Los Angeles Times that Ohtani is viewed as a victim who was hoodwinked by the interpreter. For a player viewed as almost “flawless”, there were practically no reports in Japan that cast doubt on Ohtani, Abe noted.
Natsuko Aoike, who covers the Dodgers star for Japan newspaper Tokyo Sports, described the scandal as a “major, major story”, on par with the media coverage of a presidential election. Even before the scandal, Ohtani typically garnered top headlines on a daily basis, Aoike explained.
A plan to combat illegal betting
Last month, MGM Resorts broke ground on MGM Osaka, an $8.9 billion casino resort planned in Japan’s second-largest city. The nation’s first gambling-related resort is projected to be finished by the fall of 2030, although there is no indication that sports betting will also become legal.
As illegal sports betting proliferates, many foreign countries have engaged in information-sharing initiatives with the Council of Europe as the base of operations, the authors wrote in the CSEP study. The initiative is based on the Macolin Convention, a legal instrument and the only rule of international law on sports manipulation.
While the Japanese council has formed a study group to discuss measures against illicit sports betting, the nation has yet to implement a system based on the convention, according to the CSEP.