We do not handle immigration procedures. For naturalization and other procedures, please find another specialist. The below article is just for your information.
If you change your nationality to Japan, your last name can be changed. If you are married to a Japanese, your last name can be changed to your spouse’s name.
Japan does not allow dual citizenship, so if you acquire Japanese citizenship, you will lose the citizenship of your home country.
2) Japanese Common Name (Tsushomei | 通称名)
At the Japanese city halls, foreigners can register a Japanese Common Name (通称名) if necessary. If you have any questions about this procedure, please inquire at your local municipal office.
General Information from Shibuya City Hall, Tokyo (Other city halls should also require similar documents.)
3) Changing the Name in the Home Country
If you do not intend to change your nationality and a common name is not sufficient, you may have to change your name in your home country. This is a matter of law in your home country, not Japan. You will have to check the procedure for changing your name in your home country.