Some people have been bitten by the Bitcoin bug, bidding up its value to above $1,000 for just one invisible "coin". Others have been bitten by scams, losing real money they paid only to be "hacked".

The digital currency seems mysterious to a newcomer and yet most impressive when a serious business dinner ends with payment to the waiter with a casual brush of a smart phone. The former tradition of a comical pretense of who pays the bill, with grabbing of wrists and fumbling for cash or card, has given way to an aura of awe as a new avant-garde era makes being generous look cool.

China now transacts half of the global Bitcoin volume and is a leader in pushing up the exchange rate. A schoolteacher cum computer geek named Li Xiao who signed up at the outset five years ago now has Bitcoins worth millions of US dollars. It's time for those not in the know to understand this new phenomenon.