Japanese buying JR PASS: what documents to take?

Good morning,

Situations like this can indeed get a little tricky so it is good that you are preparing well.

I believe that your marriage certificate would suffice, given that it states your name and her's in roman letters.
It would of course help if you could acquire a copy in English from your local city hall.

I don't know how valuable a copy of your Koseki may be but it may be a good supplement to your Polish marriage certificate.

An ID card alone is not enough as some proof of a foreign address is required. What you could do is print one of your online bills as these usually still display the customers name and address on the top.

If your wife has a foreign passport and enters Japan under a temporary 90 day visa than no further action for her is needed.

I hope this helps!
-Daniel

Thank you! Now I can sleep better at night.

My ID has my registered address in Poland on it, so from what you wrote, I think my ID + marriage certificate should suffice, but I'll take a print-out of one of my bills with me just in case.