BEIJING - Jack Ma, the charismatic head of Alibaba, and Ma Huateng, CEO of Tencent, are locked in a tense race to become the richest person in China and Asia.

With market values of more than $300 billion each, Alibaba and Tencent are now China's biggest companies, a stark contrast to just five years ago when no tech company even made the top 10.

Anyone seeking to decode the secrets behind the rise of the two stellar companies could do worse than just look around any Beijing subway carriage. Almost every passenger, young or old, white collar or construction worker, is very likely to have their eyes fixed on a smartphone screen.

And they are not just playing Tencent's popular game "Honor of Kings," or chatting with friends. They order groceries, transfer money, watch movies, read books, book holidays, or even manage their stock market portfolios.

As in many other areas of the economy, the scale and speed of the change in China's digital sector, the mobile internet in particular, is staggering.

Over 750 million Chinese, more than half the population, are now online, 96 percent of them via smartphone, according to the China Internet Network Information Center (CNNIC).

Mobile data traffic hit 9.4 billion gigabytes in 2016, more than ten times the amount in 2012. Data traffic by mobile phone in H1 this year was 8.9 billion gigabytes, more than double the same period last year.

This is perhaps the most dynamic mobile ecosystem in the world, and the epitome of "Chinese characteristics."