Credit cards purchases, who pays the bills, and deemed remittances to Japan for tax purposes

The following question probably comes up for a fair number of couples moving to Japan with a Japanese citizen as one spouse and a non-Japanese citizen as the other spouse. Any insight others can offer would be helpful and most appreciated.

I am not a Japanese citizen and my wife is a Japanese citizen. I plan to get a spousal visa before we move to Japan. We have a credit card for which I am the primary card holder. But, my wife also has her own card that she uses. Our credit card statement clearly lists when each of us has made a purchase with our own cards. So, the records are very clear about who made which purchase, when, and for what amount.

We pay off our card balance in full each month by having the credit card company make a debit from our shared checking account. In other words, the checking account is shared by us, currently held in both of our names. My monthly annuities are the source of funds for that account.

My question pertains to when particular credit card transactions would be considered to be a taxable remittance to Japan by me, after we move there, rather than a purchase made by my wife (and therefore not taxable). If she uses her card, then the initial thought might be that it's her transaction and tax wouldn't apply. But, the monthly payments for any purchases made are at present covered by my monthly annuities, unless we make a change.

My best guess is that I should anticipate paying taxes whenever we use that credit card because the source of funds probably matters more than whose card gets used for the transaction. Maybe I'm wrong, though. Or, perhaps this isn't a clear cut case either way.

Thank you in advance for any help provided.

by InteRest_LEtuCe2467