The world of sports betting in Japan is a paradox, a shadowy dance between cultural reverence for discipline and the allure of forbidden wagers. A recent report from the Council for Sports Ecosystem Promotion (CSEP) has pulled back the curtain on a staggering trend: in 2024, Japanese residents poured an estimated ¥6.45 trillion ($44.6 billion) into illegal offshore sports betting sites, with professional baseball leading the charge at ¥528.1 billion. This isn’t just a number—it’s a seismic shift in a nation where gambling is tightly controlled, and the story behind it is as layered as a bento box.
Baseball in Japan isn’t just a sport; it’s a cultural institution, woven into the fabric of national identity. From the roar of the crowds at Koshien Stadium to the meticulous rituals of players, the game commands a devotion that rivals religious fervor. Yet, this passion has a dark undercurrent. The CSEP report reveals that illegal betting on domestic sports, particularly Nippon Professional Baseball (NPB), has exploded, with ¥1 trillion of the total wagers placed on Japanese events alone. Baseball’s dominance in this illicit market—outpacing soccer at ¥333.4 billion and basketball at ¥86.9 billion—reflects its grip on the Japanese psyche. It’s no surprise that bettors are drawn to the NPB’s unpredictable matchups and star-studded rosters, where every pitch can feel like a high-stakes drama.
The case of Ippei Mizuhara, the disgraced former interpreter for Shohei Ohtani, throws this surge into sharp relief. Mizuhara, once a trusted confidant to Japan’s baseball deity, is set to begin a 57-month prison sentence in June 2025 for embezzling $17 million from Ohtani to fuel his gambling addiction. His story is a cautionary tale, not just of personal downfall but of a broader cultural blind spot. In Japan, where Ohtani is a national hero, Mizuhara’s actions have sparked outrage and fascination, amplifying scrutiny on the country’s gambling underworld. His bets, placed through illegal bookmakers, highlight how accessible these offshore platforms have become, even for those in the inner circles of professional sports.
Japan’s gambling laws are strict, rooted in the Penal Code, which bans most forms of betting outside government-sanctioned outlets like horse racing, motorboat racing, and a limited sports lottery. These legal options, however, pale in comparison to the allure of offshore sites, which offer a smorgasbord of betting markets on everything from NPB games to high school baseball championships. In 2024, the sports lottery generated a modest ¥133.6 billion—48 times less than the illegal market. The rise of smartphones and digital payments has made these platforms dangerously convenient, allowing bettors to place wagers with a few taps, often unaware that their actions violate Japanese law. A government survey found that 3.37 million people in Japan have used online gambling platforms, with 43.5% oblivious to their illegality.
The accessibility of these sites is staggering. Japanese-language interfaces, licensed in places like Curacao or the Isle of Man, openly cater to local bettors, offering odds on everything from the NPB’s Japan Series to high school tournaments. This isn’t just a niche problem—it’s a cultural shift. Reports indicate that at least 11 overseas sites were taking bets on the National High School Baseball Championship as of March 2025, a troubling sign given the educational context of these events. Bettors, some as young as their 20s, are drawn in by the promise of quick payouts, often using credit cards or bank transfers to fund their accounts. One Tokyo office worker admitted to racking up ¥20 million in debt betting on European soccer and tennis, thinking it was a “gray area.”
The consequences ripple beyond individual losses. The CSEP report raises alarms about match-fixing, a specter that haunts any sport with heavy betting. Japan’s history with gambling scandals—like the 1969-1971 Black Mist Scandal, where players were banned for colluding with yakuza to throw games—adds weight to these concerns. More recently, two Yomiuri Giants players were referred to prosecutors in May 2025 for allegedly using online casino sites, and 16 NPB players across eight teams faced fines for similar violations. These incidents underscore the risk to the integrity of Japanese sports, particularly baseball, where even the hint of impropriety can tarnish a revered institution.
Why is this happening in a country known for its restraint? Part of it is cultural disconnect. Japan’s gambling laws, while strict, are poorly understood, and enforcement against offshore operators is nearly impossible. Unlike France, which blocks access to illegal sites, or the U.S., where 39 states have legalized sports betting since 2018, Japan remains an outlier among G7 nations, clinging to a prohibitionist stance that pushes bettors to unregulated markets. The pandemic also played a role, accelerating online betting as physical gambling dens shuttered. By 2021, access to illegal sites had jumped 100-fold from 2018, fueled by the ease of digital transactions and a lack of public awareness.
There’s also a psychological pull. Baseball’s intricate statistics and unpredictable outcomes make it a bettor’s paradise, offering endless opportunities for analysis and speculation. Offshore platforms capitalize on this, providing real-time odds and analytics that turn casual fans into obsessive punters. Moneyline bets, run line spreads, and over/under totals transform every game into a high-stakes puzzle. For some, it’s less about the money and more about the thrill of outsmarting the odds—a dangerous lure in a society where gambling carries a heavy stigma.
The response from Japanese authorities has been sluggish. The National Police Agency views betting on offshore sites as illegal, but prosecuting users is rare, and targeting overseas operators is a logistical nightmare. The CSEP is pushing for international cooperation, citing the Council of Europe’s Macolin Convention, which combats match-fixing through shared intelligence and public awareness campaigns. Yet, Japan has not ratified this agreement, leaving it isolated in the global fight against illegal betting. Meanwhile, calls to legalize sports betting domestically—potentially redirecting billions into regulated markets—face resistance. Yomiuri Giants owner Toshikazu Yamaguchi dismissed the idea, reflecting the NPB’s reluctance to embrace a system that could further complicate its image.
The Mizuhara scandal, while a U.S.-based case, has forced Japan to confront its own vulnerabilities. Ohtani, cleared of wrongdoing, remains a symbol of purity in the sport, but the fallout from his interpreter’s actions has sparked a broader conversation. Social media captures the public’s shock, with some framing Mizuhara’s 57-month sentence as a warning to others. Yet, the allure of illegal betting persists, fueled by Japan’s love for baseball and the global reach of online platforms. As one observer put it, the scandal is a “wake-up call” for a nation grappling with a gambling epidemic it’s ill-equipped to control.
This surge in illegal betting isn’t just a legal issue—it’s a cultural reckoning. Japan must balance its reverence for baseball with the reality of a digital age where bets are placed faster than a fastball. Whether through stricter enforcement, public education, or a bold rethink of gambling laws, the country faces a pivotal moment. For now, the game goes on, but the stakes off the field are higher than ever.