I am a Japanese citizen in China. I want to renew my Japanese passport in China and still use the Chinese visa from my old passport.
Is this possible at the Japanese Embassy in China?
If you renew your Japanese passport and are able to keep your old one, then yes, you can use your old and new passports together for travel to and from China.
This is stated in Timatic, a database used by airlines checking passengers.
Valid visas or resident permits in expired passports are accepted if holding a new valid passport of the same nationality. The personal information on both passports must be the same.
You have to renew your passport and keep the old one is a common procedure. Then you have to travel with your two passports, the old one with the valid visa and the new one.