All-night gaming marathons will soon end for some Chinese kids: internet giant Tencent began limiting daily playing times on its smartphone smash hit "King of Glory" on Tuesday to "ensure children's healthy development".

Young players will be restricted to one or two hours on the mobile online multiplayer battle game, which boasts 80 million daily users, as concerns grow in China that long periods online are posing a serious threat to the country's youth.

But investors are not playing around: Shares in Tencent, which ranks first in the world for gaming revenue, slumped 4.13 percent on Tuesday -- its biggest single-day drop since February 2016.

"The limits on the game King of Glory is part of the reason for the (shares slump) today," Sam Chi Yung, a Hong Kong-based senior strategist for South China Research Limited, told AFP.

"This will affect Tencent's earnings eventually as players would buy equipment and stuff when they played the game."

King of Glory became the world's highest grossing game this year, with an estimated first-quarter revenue of around 6 billion yuan ($883 million), according to Xinhua state news agency.

- Irrational consumption -

Some 24 million young people in China are estimated to be internet addicts.

State media reported in April that a 17-year-old gamer in southern Guangdong province suffered a type of stroke after spending 40 consecutive hours playing "King of Glory".

Editorials in the People's Daily Monday and Tuesday called on gaming platforms like Tencent to be aware not only of the markets, but also of their "responsibilities" to society.

The Communist Party mouthpiece suggested that "King of Glory" may be "'entrapping' life" instead of "entertaining the public."

"Smartphones are ubiquitous and the mobile gaming market is exploding," one editorial said, "but cellphones cannot be reduced to 'black cybercafes' or even 'grenades.'"

Users 12 years of age and younger are now limited to one hour of play a day, and will not be permitted to sign in after 9pm, Tencent said in a statement over the weekend.

Users between 12 and 18 years of age are limited to two hours per day.

According to the company, which called its new controls the "three broad axes," those who play beyond the allotted time period will be "forced to go offline".

Tencent will also place caps on the amount of money that underage users can spend on the platform, so as to rein in "minors' irrational consumption".

Additional measures implemented earlier this year include a real-name authentication system and software that enables parents to place electronic locks on the game.

- 'Spend time with children' -

Users on the Weibo social network, however, were sceptical that avid gamers would be deterred.

"What's the point," one commenter said. "Most elementary schoolers are already using their parents' accounts."

"Those little devils will just steal their parents' ID cards to register," another chimed in. "And soon there will be a big black market for adult-age accounts!"

China, which became the first country to declare internet addiction a clinical disorder in 2008, introduced draft legislation in February that would ban minors from playing online games between midnight and 8am.

But in the current absence of "clear regulations to guard against mobile gaming addiction," Tencent said, "we have decided to take the lead ... and dispel parents' concerns".

"We also call on parents to spend more time with their children, to allow them to feel more the warmth of growing up."

In recent years, some Chinese parents have begun sending their children to intensive internet addiction "rehabilitation" centres known for their military-style tactics, including electroshock therapy and beatings.

source: AFP