Bitcoin is the most liquid of all the cryptocurrencies. Japan’s decision to start recognizing it as legal tender in April seems to have led directly to the current run-up. Markets in Japan and South Korea recently priced it at $2,350 per coin. This seems to be fueling a rally in other cryptocurrencies.

Markets like Bitfinex, Bitstamp and BTC-e make it easy to set up an account and trade Bitcoin, but prices vary widely. There are also Bitcoin markets around the world — it’s a global currency after all — and their prices can vary wildly, too.