SAN FRANCISCO • Until recently, China was a centre 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 the bitcoin was created in 2009, it has become increasingly popular around the world because of its anti-establishment appeal. But in South Korea and Japan, the countries' most important institutions have been leading the way.

Japanese trading took off after the government in April approved legislation that creates the world's first national licensing programme for virtual currency exchanges. Last Friday, the government announced it was giving the first licences to 11 exchanges, including bitFlyer.

In South Korea, trading ticked up after Samsung announced in May that it had joined a large alliance of global companies aimed at finding corporate use for the software behind Ethereum. Ethereum includes a virtual currency, Ether, but it is also software that allows parties to enter into what are essentially legal agreements, or smart contracts, involving the money.

NYTIMES