There’s still much we don’t know about the betting scandal that has enveloped Shohei Ohtani, baseball’s golden boy and possibly the greatest to ever play the game.

What is his involvement with the illicit gambling involving at least $4.5 million that resulted in the firing of his longtime interpreter and friend? Did he help cover Ippei Mizuhara’s losses, as was first reported, or was he the victim of theft? Does the betting extend to baseball itself?

But for Ohtani’s millions of Japanese fans, one additional mystery should be how attitudes in the U.S. toward sports betting have shifted so quickly. Since a landmark Supreme Court decision in 2018 opened the door to this kind of gambling nationwide, the speed at which U.S. leagues have embraced it would put a Shohei fastball to shame.

Accelerated by the pandemic and smartphones, teams have scrambled to embrace official betting partners and advertisers, even adding sportsbooks at stadiums. Just a day before the revelations about Ohtani’s interpreter, the National Basketball Association said it would integrate real-time betting right into its NBA League Pass app.

Coming from Ireland, the home of market-leading owner of Paddy Power and FanDuel, Flutter Entertainment, and a country where sports betting has long been prominent, the pre-2018 attitude in the U.S. always struck me as strangely puritanical. But these days, as an avid watcher of the Ultimate Fighting Championship mixed-martial arts promotion, I’m more struck at how gamified the viewing experience has become. The broadcast is constantly encouraging, indeed almost demanding, that at all times viewers gamble in new and more complex ways. Sign up for your DraftKings account! Look at the odds on this three-way parlay! Bet now!!

Here in Japan, the home country of Ohtani and his erstwhile interpreter, sports betting remains much more tightly controlled. Wagers are allowed on just four sports — horse racing, motorboat and motorbike racing and keirin competitive cycling — which are each tightly controlled by various government ministries and don’t directly involve private-sector firms.

Nonetheless, this is big business: Keirin brought in over ¥1 trillion in revenue in the 12 months ended March 2023; horse racing brings in four times that amount. However, if you fancy the Hanshin Tigers for this year’s Japan Series, Yuya Osako to be top scorer in this year’s J. League or rookie Takerufuji to win the Spring Grand Sumo Tournament, you’re out of luck, legally at least. Japan doesn’t allow betting on these sports, outside of some low-stakes lottery-style flutters on J. League soccer as well as basketball matches.

There’s no better illustration of the differing attitudes to the U.S. than the J. League’s issuance of a warning to fans last month of the potential legal troubles that can come from placing bets on sites outside Japan, which is illegal. Of course, there’s also outright illicit gambling, as Mizuhara is accused of — multiple players from the Yomiuri Giants baseball team were found to have bet on baseball games almost a decade ago.

The popularity of such unlicensed betting — along with other forms of gray-area gambling like the ubiquitous noise hazard of pachinko and low-stakes games of mahjong — shows that the market is there. An estimate from Cyberagent (which runs online betting apps for keirin and motorbike races) puts the potential size of the sports betting in the country at some ¥7 trillion ($46.3 billion) a year.

Since a surge in interest in gambling during the COVID-19 pandemic, various Japanese government panels have discussed the possibility of legalizing sports betting. Any move in that direction is likely to take a long time, however. This is the country that began discussing legalizing casinos in 2013, but won’t open the first until 2030, after a protracted debate about gambling addiction. That concern is amplified when it comes to sports betting. It’s much easier to push a button on your smartphone during a match than go all the way to the yet-to-be-built casino in Osaka.

And in the U.S. rush to develop sports betting markets, the dangers of match-fixing haven’t received the attention they deserve. That seems odd for the country that went so far as to ban baseball legend Pete Rose for life for betting on his own team to win. The rise of prop betting — which allows gamblers to bet on statistics other than simply the result, from the number of yellow cards in a soccer match to the passing yards in an NFL game — make fixing and suspicious betting patterns harder to track.

A Sportsradar survey found a 34% increase in suspicious matches in 2022 from the year before in 12 sports including soccer and tennis across 92 countries. The FBI has been reportedly investigating fight-rigging in the UFC since 2022. Japan has experience here too, with multiple sumo wrestlers implicated in a match-fixing scandal in 2011 — one that involved much less money on the line than U.S. sports.

There’s doubtless more to come from this story as we learn how Ohtani was involved, distracting from his greatness on the field. That’s why Japan’s most famous asset should serve as a cautionary tale about a rush to permit — and promote — more sports betting.

Gearoid Reidy is a Bloomberg Opinion columnist covering Japan and the Koreas.