After living in China for years, one of the habits I have developed is not carrying a purse around.

Online payment services such as Alipay are now so popular in China that I, like most of my friends and even my parents, barely carry any cash while shopping, no matter if I am visiting a supermarket for groceries or dropping by a cafe for a latte, or even tipping a waiter in a hotel.

So, one day during my vacation in Japan in October, like always I got out of the hotel taking nothing but my cell phone. Only after the taxi I rode on drove for some two kilometers did I notice that I don't have cash to pay for the ride.

I asked the driver if we could drive back to the hotel for my purse. He surprised me by showing the QR code of Alipay, a mobile and online payment platform operated by Ant Financial Services Group, an affiliate of Alibaba Group, and said it was okay for me to just pay by scanning it.

Even more surprisingly, the driver said he knows Alipay is getting more popular in Japan as many tourists prefer a cashless way of shopping, with a scan of a QR code rather than a handful of banknotes and coins.