Tokyo has once again become the center of a world-wobbling virtual financial crisis. Let me emphasize the word virtual. That’s because the world’s best-known and perhaps largest exchange of the virtual currency known as bitcoin — Mt. Gox, located in Tokyo’s Shibuya district — appeared to have all but collapsed last week.

And with that exchange out of operation, uncountable amounts of wealth are now missing.

The Japanese government, which has until recently paid little attention to bitcoin or its largest exchange, has expressed concern and appears to be chewing over the matter.

What are bitcoins? A bitcoin is a virtual currency that is produced by the Bitcoin computer program. The program was released in 2009 by a computer genius who has used the pseudonym Satoshi Nakamoto.

Who is that? I suspect he is the cyber equivalent of Mr. Kobayashi in the film “The Usual Suspects” — but these days he seems a lot closer to Kobayashi Maru. (If you don’t understand the oblique reference, watch some more “Star Trek.”)

The bitcoin program runs on the computers of anyone who joins up, and it is supposedly set to release currency only in regular increments. Bitcoin can be moved between digital wallets using secret passwords. The codes are supposedly extremely heavily encrypted and uncrackable. Bitcoin advocates see it as a revolutionary new way of moving money around the world. Critics have viewed it as pyramid scheme or a huge opportunity for investment fraud and/or money laundering.

For those of you who are not into finance, which includes me, you can look at the trade in bitcoin as something akin to foreign-currency trading — or gambling.

The value of bitcoin fluctuates tremendously. It reached a peak of $1,200 and is now floating at around $500. If you buy low and sell high, there’s a lot of money to be made. The same thing can be done with yen to some degree — especially if you know when Prime Minister Shinzo Abe is planning to visit Yasukuni Shrine or new NHK President Katsuto Momii feels moved to make another crazy remark. (Hint: Sell your yen before either of those occurrences.)

Mt. Gox was founded in 2009 as a trading-card exchange before, from the following year, it became a major bitcoin exchange.

Up to 70 percent of the world’s bitcoin trades went through the site at its peak. On Feb. 23, the current CEO, Mark Karpeles, quit the board of the Bitcoin Foundation, which oversees and develops the virtual currency. Shortly afterward, while rumors proliferated that several hundred million dollars had been hacked out of Mt. Gox’s accounts, the site simply shut down.

Millions of dollars worth of currency is now lost (temporarily, or not) in cyberspace. Thus bitcoin has became a “bit” of a headache for the Japanese government. Top government spokesman Yoshihide Suga said the authorities — including the police and the Financial Services Agency — were collecting information on the bitcoin trade in Japan and considering regulatory action.

However, within the FSA there is considerable skepticism. One senior official said, off the record, “It’s like regulating Pokemon cards. People think they have value and they buy and sell them. If someone wants to pay ¥700,000 for a zebra-striped Pikachu, that’s their choice. Bitcoin isn’t a real currency and thus it’s not really under our jurisdiction.”

While no one is accusing Mt. Gox or its CEO of fraud, there have been cases of virtual currency being the center of criminal investigations in the not-so-distant past. In March 2010, the Tokyo-based founder of the bankrupted L&G K.K., who promoted the use of its “enten” quasi-currency in a fraud scheme, was sentenced to 18 years in prison for swindling investors. The entire scam was estimated to have totaled more than ¥500 billion in damages. One way the firm collected funds was by issuing its own enten currency, which they claimed could be used at company-sponsored bazaars nationwide and on the Internet. However, that currency was issued in exchange for investing in the company — hence enten and bitcoin aren’t quite the same thing.

If the Mt. Gox money has been stolen then that would be a crime — but the management would be the victims, not criminals. If the money was siphoned off intentionally, or if the firm was doing transactions knowing they were going to go under, they could be involved in fraud. Right now, no one seems to know what’s going on.

Of course, this isn’t exactly the first time billions of yen have just vanished into thin air from a financial institution in Tokyo.

The FSA noticed in 2012 that AIJ Investment Advisers, a pension-fund manager, had somehow lost about $2 billion. Poof! And that was a firm under FSA supervision. To top it off, for years before they took action, the FSA had received numerous complaints about the firm.

So do please forgive me if I don’t think Japanese government intervention will make bitcoin exchanges any safer to use.

In 2012, by the way, MRI International — an asset management firm with an office in Tokyo and mostly Japanese clients — was investigated by the U.S. Securities and Exchange Commission on suspicion of defrauding its customers of ¥130 billion. Thank goodness the company was registered in Las Vegas or the FSA would have looked like they were asleep at the wheel . . . again.

Despite skepticism about bitcoin, some casinos in the United States accept bitcoin payments — as do some Tokyo restaurants. Until the implosion of Mt. Gox, bitcoin seemed to be moving toward becoming an accepted currency. And while the problem is big, it will not necessarily put an end to bitcoin trading or use in Japan.

Traci Consoli, the American manager of Tokyo restaurant and event space The Pink Cow, has not been dissuaded. “We will absolutely continue to accept bitcoins,” Consoli said. “Just because we made the mistake of going with one company who structured their business badly doesn’t mean bitcoin overall is not a good thing. I had friends who lost most of their life savings in the subprime crash, and that was entirely regulated. It can happen. We’ll continue to redeem it.”

This column is written days in advance of publication, so perhaps by the time you’re reading this, Mt. Gox will be back online.

Perhaps their clients will have their virtual money back in their virtual wallets — or perhaps they will have cashed it in for cold hard yen. Somehow, I feel that probably won’t be the case.

Personally, I’m going to start asking The Japan Times to pay me with bags of rice. That’s a currency I know will be good for at least a few months.

Update: Mt. Gox filed for bankruptcy protection in Japan on Friday.