The Embassy of China only accepts applications for marriage registration from citizens of People's Republic of China (PRC) and China, and citizens of these two countries must legally stay in Japan for more than six months. Both men and women who want to get married must go through the marriage registration formalities at the embassy in person. Only a man who is not less than 22 years old and a woman who is not less than 20 years old can register for marriage at the embassy.
The Embassy of China does not accept applications for marriage registration where one party is a foreign citizen. Please go through the relevant formalities at the Japanese city or regional service office.
The required materials are as follows:
China passports and photocopies of both parties.
Original entry certificates of original tickets (valid within 3 months) of both parties.
3 photos of both parties (4×5cm).
Everyone should fill out a declaration of applying for marriage registration.
Fill in the "Marriage Registration Review Processing Form"
Basic fee (4 working days): 5000 yen.
Expedited fee (2 working days): basic fee +3000 yen.
I hope it helps you.
Feel free to consult if you have any questions.