SAN FRANCISCO — Until recently, China was a center of Bitcoin activity while the rest of Asia looked on with little interest.

Now, the tables have turned.

The Chinese government has been clamping down on virtual currency activity at the same time that hundreds of thousands of Japanese have thrown themselves into Bitcoin trading, making Japan’s main Bitcoin exchange, bitFlyer, the largest in the world in recent weeks by some methods of counting.

South Koreans have also shown a sudden interest in virtual currencies, though they have generally opted for Bitcoin competitors like Ethereum and Ripple. Trading has been so popular that two South Korean exchanges, Bithumb and Coinone, have set up storefronts in Seoul that people can visit to buy and sell in person.

Since Bitcoin was created in 2009, it has become increasingly popular around the world because of its anti-establishment appeal — a virtual currency that is challenging governments and financial institutions. But in South Korea and Japan, the countries’ most important institutions have been leading the way.