The Social Security Agreement between China and Japan took effect on September 1, 2019.
In the future, with proper applications, Japanese citizens who are employed by Japanese companies while dispatched to work in China due to the employment relations would be exempted from paying basic old-age social insurance in China.
The valid period of social insurance exemption for a dispatched Japanese citizen should be no more than five years. Where the dispatch period is more than five years, with the permission issued by the in-charge government department in China or Japan, the valid period would be extended.
For the detailed procedures in China, please refer to Notice of the General Office of the Ministry of Human Resources and Social Security on the Implementation of the Social Security Agreement between China and Japan issued by the General Office of the Ministry of Human Resources and Social Security on Aug. 27, 2019.
AGREEMENT ON SOCIAL SECURITY BETWEEN THE GOVERNMENT OF JAPAN AND THE GOVERNMENT OF THE PEOPLE’S REPUBLIC OF CHINA
https://www.mofa.go.jp/mofaj/press/release/press1_000223.html
Notice of the General Office of the Ministry of Human Resources and Social Security on the Implementation of the Social Security Agreement between China and Japan
http://www.mohrss.gov.cn/gkml/zcfg/gfxwj/201908/t20190828_332003.html