BEIJING // It is a bright spring day outside, but no sunshine reaches the interior of this dimly lit, windowless internet cafe in the Chinese capital.
Faces stare into rows of screens and the air is stuffy from the several people smoking as they play online games.
The less-than-attractive environment does not seem to keep the customers away: even on a weekday morning there are plenty of them.
In a country where the number of internet users is growing by 200,000 a day and is now above 450 million, it is perhaps not surprising the cafe enjoys brisk trade.
While the internet is an occasional distraction for some, it has taken over the lives of others to an alarming degree. The country's online gaming addicts are reported to run into tens of millions.
Theirs is a world where animated figures bear swords or guns as they tear through spectacular landscapes dotted with Chinese temples.
"It's bad for your health to play too much, but it's addictive," said Li Yangyang, 24, a hotel employee, who spoke in the middle of one of his regular five-hour sessions.
"If I don't have anything to do during the weekend I like to stay here the whole day. At lot of people play too much."
The dangers posed by overuse of the internet have become acutely apparent in China, with a series of deaths in recent years linked to online gaming.
One teenager threw himself off a Tianjin highrise after 36 hours playing World of Warcraft, a multiplayer online role-playing game, a 16-year-old boy in Guangzhou stabbed his mother to death in 2007 after she refused to give him money to use an internet cafe, while at least two young people were beaten to death at boot camps that use early-morning wake-up calls, military-style marches and counselling sessions to wean youngsters off their internet addictions.
In the latest gaming tragedy, a man collapsed and died last month after a three-day non-stop gaming marathon at an internet cafe on the outskirts of Beijing. The 30-year-old is said not to have slept, and barely eaten.
Wei Ping, who works at an internet cafe to the east of the city centre, said long stints were nothing unusual.
"We have some customers who play for 24 hours or 48 hours," he said. "They do not eat or drink or even have a cigarette. You do have people who are addicted."
A study from Singapore, released in January, found about nine per cent of young people were judged to have a "pathological" gaming habit, playing on average 31 hours a week. The research, which looked at more than 3,000 secondary school pupils, found over-use of online games can lead to anxiety, depression, poor school performance and social phobias.
"If you get into really addictive behaviour, there's a danger of becoming depressed. [Addicts] can be isolated in school and have conflicts with their family," Angeline Khoo, one of the study's authors and an associate professor at Singapore's National Institute of Education, said by telephone.
But gaming is not all bad. Dr Khoo said youngsters can improve their cognitive abilities, and even develop social skills if playing with other people.
Researchers from Hong Kong last year also found benefits with young people who had made friends through online games, which can be played simultaneously by multiple people in different parts of the world. The youngsters showed improved social skills and self-esteem.
"Most kids who reported having online friendships that were pretty strong were happier and more well-adjusted than those who didn't," said Catherine McBride-Chang, a professor in the Chinese University of Hong Kong and one of the study's two authors, in a telephone interview.
However, she warned that time spent playing should be limited to one to two hours per day for young children.
"It's clear if you're playing too much there's a correlation [with] your academic performance, and it goes down," she said.
Youngsters in Asia, including China, may be particularly vulnerable to addiction because the pressure to do well at school leads them to take refuge in online gaming, said Dr Khoo.
Indeed, the father of Deng Senshan, who died in 2009 after being beaten at a boot camp for online addicts, said in an interview after his son's death that the 16-year-old spent so much time gaming because "it was his way out of the pressure of being a student".
Weaning China's young off their addiction to online games may prove difficult. Lin Yan, a 20-year-old telecommunications student who insisted her habit of two to four hours a day was under control said, for many young people, the computer offered greater rewards than anything else.
"In some games, you can be an emperor, even if in real life you could never become one," she said while taking a few moments away from a game called Rose Garden that allows players to plant flowers and vegetables online.
Her view was echoed by Guo Xiaojian, 25, who works in an internet cafe and plays games for three to four hours a day.
"For me, when I was at school studying, I was never able to be in first place," he said. "But in internet games, I have the chance to come first, to win. I think it's much better than real life."