all Japanese government documentation require a Kanji?
Thank you for your advise, yes we are starting to realise this isn't as simple as we thought or hoped!
Apparently, all Japanese government documentation require a Kanji name and so the Japanese wife will not be able to change that no matter what her name is in other countries?
So now that we have a new 'Koseki', that would record the Japanese wife as the 'koshu', with her Japanese maiden name. We believe this is also the case even if she takes her Western husband's family name after marriage, though the 'Koseki' will then acknowledge in (brackets) next to her Japanese maiden name that she is known as another surname outside of Japan..
We are in the process of receiving advise from Japan (We are based in the UK) but according to her family over in Japan, it's been received with a slight '???' as it seems not such a common request. The process of going to the family courts have been mentioned and also fees involved - which, it will also cost in the UK to have the surname changed by deedpole anyway so not so surprising but probably we have faced ore opposition then support over a double barreled Japanese-Western surname idea.
Is mixing two names from 2 different countries not such a good idea then we wonder? This doesn't feel too unnatural to us, as it feels similar to a Japanese man/woman marrying and inheriting his/her Western partner's family name: eg, Hanako Jones or Taro Smiths