Tencent says that if you are under 18 and spend over 500 yuan (US$77) on in-game purchases in a day, it will alert your parents.

The new function is on trial right now, and not a moment too soon: Tencent has been sued by Chinese parents, after their children spent thousands of dollars on in-game purchases.

For instance, in 2017, an 11-year-old girl spent 100,000 yuan (US$14,700) in Honor of Kings (known as Arena of Valor in the West).

Honor of Kings is so popular that there are smartphone arcades where children go to play -- and hide from their parents. (Picture: SCMP)

Parents put the blame on Tencent, saying it made in-game purchases too easy for underage gamers to splurge on in-game items. Each item purchase is just a tap away, since payment is linked with Tencent’s own WeChat Pay, one of the country’s biggest digital payment platforms.

Tencent lost many of those lawsuits. One high-profile lawyer said he forced the tech giant to return more than US$5,700 to five families.

So how will they implement it? Tencent is dedicating a team of 200 to identify gamers under the age of 18. Players have to submit their real name, age and ID number during registration.

There’s an obvious counter to this: What if they lie? What if they use a parent's name instead? Tencent has an answer for that too: They claim they’ll be able to tell if it’s a minor playing by their erratic spending.

One thing Tencent doesn’t have an answer for is whether 200 people is enough to wade through an enormous player base -- Honor of Kings alone has over 200 million players.

This isn’t the first time that Tencent has restricted its games from being too accessible to underage gamers.

Tencent put a playtime limit in Honor of Kings, stopping those under 18 from playing for more than 2 hours a day (and if you’re under 12, you can only play for an hour).

It came after an editorial from state media called the game "poison" and a "drug" that harms teenagers. It wiped US$17.5 billion off Hong Kong-listed Tencent’s market value in just one day.

In March, Tencent CEO Pony Ma said the company would introduce digital contracts that would allow parents and children to negotiate time limits for playing Honor of Kings.

The contract can link playing time to tasks such as completing housework and study, thus encouraging positive behaviour in children by rewarding them.