For all the high-powered wizardry that the phones in our pockets contain, it is perhaps comforting that many of the most popular and lucrative companies that the smartphone age has created revolve around the very human act of conversation.

Facebook, Twitter, WhatsApp and Snapchat, to mention just a handful of the world’s most valuable technology companies, are fundamentally about communication, and have all grown to hundreds of millions of users around the world.

But for all of Silicon Valley’s global ambitions, on the other side of the world they are sideshows to their Asian equivalents. In China, which cuts off many American internet services, the smartphone chat app WeChat dominates. And in Japan, millions of citizens communicate not through Facebook or WhatsApp, but via a five-year-old app called Line.

The service, which was responsible for the biggest technology IPO of the year when it floated in Tokyo and New York at a $8.6bn (£6.8bn) valuation in July, is a phenomenon in the East, where it has seen off the challenge of its bigger Western competitors.