An investigation launched by Chinese authorities at the request of a Japanese industry group has led to the closure of an illegal website that hosted pirated versions of Japanese animation, movies and soap operas.

The Chinese crackdown targeted four people in their 30s who were suspected of involvement in running the piracy site known as "B9GOOD," officials with Japan's Content Overseas Distribution Association said.

The site has been popular with fans of Japanese movies and anime since its launch 2008.

It was accessed more than 300 million times in the two years until last month and in its busiest periods over 15.8 million times per month.

The Japanese association had conducted an investigation, together with cyber security experts, and found that the website -- which was mostly accessed by people in Japan -- was run from China. The group repeatedly demanded that the operators remove pirated content from the website.

The crackdown by authorities in Jiangsu Province was prompted by a tip from the Japanese side, resulting in the closure of the site.

Officials believe the operators have made more than 100 million yen, or over 759,900 dollars, in revenue running the website.

The Japanese association has ramped up efforts to provide information to overseas authorities, as piracy site operators move out of Japan.

The group says the latest case was the first time for operators of a China-based piracy site to be subjected to a law enforcement crackdown based on a tip from the Japanese side.