China has implemented an online video game curfew for minors, a move meant to prevent addiction to games and to improve health among children and teens. According to government rules issued Wednesday, game companies cannot let players younger than the age of 18 play on their online game networks between 10 p.m. and 8 a.m. Chinese officials have been concerned about minors becoming addicted to games. The matter is "worthy of high attention," according to an official government interview posted by Xinhua News Agency, the country's state news agency. The new rules are "of great significance and practical role in strengthening and improving the management of online games, effectively protecting the physical and mental health of minors, and creating a literate and fluent network space," the official says. China is the world's largest video game market, with 626 million video game players, and revenue generated of $24.8 billion in 2018, according to consulting and research firm PricewaterhouseCoopers.