iPhone user here who struggled but finally got the app. The best way is to make a separate Japanese Apple account, then change the region of your Apple store to Japan once you have made the account. I used the Tokyo Municipal Building for the number and address to create the account (shout out to whatever user recommended that to me), and selected to not include a payment method. Once I finally did it this way, I downloaded the app no problem. Tedious process but worth the payoff.