If a citizen of the U.S. were to marry a Japanese citizen would the Japanese citizen have dual citizenship in both countries? I want to marry my girlfriend who is Japanese but she does not want to lose her Japanese citizenship. I though she would be able to keep it if we get married but she says she will lose here Japanese citizenship if we get married. Could someone please shed some light on this for me?
Thanks in advance for your help!

Thanks in advance for your help!
