Sales of the PlayStation 4 in China have yet to take off, and Sony says a lot of that has to do with censorship.

The PS4 went on sale in China in March for 2899 yuan (£307), with Knack, Rayman Legends, Trials Fusion and Dynasty Warriors 8: Xtreme Legends Complete Edition available. There were also a couple of China-focused PS4 games: King of Wushu and Mr.Pumpkin's Adventure.

China lifted a 14-year ban on game consoles in 2014 with the establishment of the Free Trade Zone in Shanghai, and both Sony and Microsoft moved quickly to release their consoles in the potentially huge market.

At the launch of the PS4 in November 2013, Sony Computer Entertainment boss Andrew House told Eurogamer he believed the console had the capacity to exceed the sales of the PS3 because of the emergence of new markets - including China.

But China's strict censorship rules have limited sales of PS4 in the country, House told Reuters this week.

"We are still challenged somewhat with a censorship regime that we have to work with. This can be time-consuming," House said.

"I don't think it has been a kind of a rocket launch start."

The Chinese government's rules prevent the release of "anything that promotes obscenity, drug use or violence", which rules out the likes of Grand Theft Auto 5.

Anything that "insults, slanders or violates the rights of others" is also disallowed, as is any gambling-related content or features.

There are a number of extra clauses to block content that could specifically upset China's interests - anything that threatens the country's reputation, for example, or its natural unity, or its sovereignty, or its territorial integrity. Anything that runs contrary to its policy on religion is also out - including anything that promotes cults or superstitions.

Game updates (such as DLC packs or expansions) must also face this approval method.

"Things that are hostile to China, or not in conformity with the outlook of China's government, won't be allowed," China's Ministry of Culture head Cai Wu explained at the time. "We want to open the window a crack to get some fresh air, but we still need a screen to block the flies and mosquitoes."

Of course, there are other China-specific issues that hamper the official sale of both the PS4 and the Xbox One in the country, including the relatively high price of the consoles, the prevalence of the already-established grey market, and the preference among gamers for PC and mobile titles.

Despite this, House said he still saw "tremendous potential for gaming as an entertainment medium in China".