hi all, i am not sure if this is not forum to ask this question but anyways.. I am a US citizen and Taiwan citizen (Taiwan allows dual citizenship). I married my wife, who is Japanese, IN Japan, and applied for her to come to the US through the DCF process. Anyways, she's here now and we got her permanent green card already. Now, when we got married in Japan. I use my US passport as my ID, so on the marriage certificate in Japan, I am listed as American. Now, I am also registered as citizen in Taiwan, and I would like to add my wife to the registery in Taiwan too. Because we might move to Taiwan one day. However, official in Taiwan wants me to show proof that I am also a Taiwanese when I married her in Japan. Yeah i know, didn't make sense to me either. So, anyway knows a way that I can do that? The Taiwan embassy in Japan said they can't do it, there's no proof I am Taiwanese during the time I married my wife. So, I am a bit lost now. In addition, we don't have a english marriage certificate since it was done in Japan. We translated one when we apply for her visa but they took that piece of paper already. I could do another translation and get it notarized I am sure. And then give it to the Taiwan embassy in US here, and show them my Taiwan passport too and have them add a line to the translation that specify that I am Taiwanese too.
I hope i havn't confuse ya all. If anyone had any similar experience, any help would be appreicated. Thanks.

DCF works for US Citizenship but not Taiwan Citizenship.

You should apply your wife's registry at Taiwan instead of Taiwan Embassy at Japan.
Since you are citizen of Taiwan, you should have passport of Taiwan. Fly back to Taiwan with your Taiwanese passport when entering custom. Go to relevant government institute to register your marriage with your wife. Consult with local official there in Taiwan. They will give you the detail procedure. She will get her Taiwanese citizenship as long as you are citizen of Tawan. Good luck.