Japan's latest "idol" band, the Virtual Currency Girls, took to the stage for their debut concert Friday to educate the public about cryptocurrencies -- playing to frenzied fans waving their arms and chanting together.

"Our brains are fried as we are studying every day" about virtual currencies, said the group's leader Rara Naruse, 18, as they began their live concert in Tokyo.

The band hopes to promote the idea "through entertainment" that virtual currencies are not just a tool for speculation but are a wonderful technology, she said.

Each of the eight girls in the band, known in Japanese as "Kasotsuka Shojo", plays a character representing a virtual currency such as bitcoin, ethereum or ripple.

Wearing character masks, frilly mini-skirts and "maid" aprons complete with knee-high socks, they performed in a small hall packed with dozens of hand-picked fans and media people.

Their tunes included their debut song, "The Moon and Virtual Currencies and Me", which warns against fraudulent operators and urges people to make sure of their online security.

In keeping with the theme, fans were required to pay 0.001 bitcoin (around $15) -- to take a picture with one of his favourite performer. The price includes a hand-shake and some small-talk.

The girls are paid in bitcoin and payment for admission to future performances and merchandise will only be accepted in virtual currencies.

Their message appeared to be getting through.

One fan, 43-year-old Hiroshi Kasahara, who runs an ad agency, said: "I have been trading stocks and forex but not bitcoin or other virtual currencies as I was a bit scared of them."

"But I feel like opening an account" if the group accepts payment only in virtual currencies, he told AFP.

Makoto Sato, 42, said the idol group had given him "a good introduction" to the world of cryptocurrencies.

"I may well give it a try as it can be a catalyst to make life more convenient and fun," said the 42-year-old office worker.

At the end of the performance, fans cheered and clapped, with one screaming out: "Can't stop loving you!"

The group is tapping into a rich seam in Japan, where bitcoin is recognised as legal tender.

Nearly one-third of global bitcoin transactions in December were denominated in yen, according to specialised website jpbitcoin.com.

The group's launch comes on the heels of a recent market frenzy which boosted bitcoin up to nearly $20,000.