You may need to use a VPN when you create a Japanese Apple account.
Go to appleid.apple.com/account.
Fill out the form. *Email must be different from your main Apple ID (if you already have one) or your main email address (in case you plan to have a main Apple ID).
Choose "Japan" from the list of countries.
Fill out the form and submit.
Check your email for verification code.
And you're done.
Open iTunes. Sign out of your iTunes account if you are signed in.
Go to the store. Scroll all the way down to the bottom until you see a flag of a country. Click on it.
Search for a free app, click the app, and click Get.
Note: You MUST search and try to download a free app to have a "None" option for payment when creating an account.
Click Create Apple ID.
Enter a clean email address, password, and other details. Click Continue.
Note: You may use your existing Gmail account by adding "+1" at the end (e.g. "example+1")
The Payment Type “None” should be pre-selected for you. Leave the gift card area blank. If it is not pre-selected, choose option “None”.
Input any Japanese hotel address, or use the following
Postal Code: 160-0023 Select “Tokyo” from the drop down box.
Type: “Shinjuku-ku” in the box to the right of Tokyo.
Address: “Nishishinjuku 6-12-6” or anything you want. Leave the rest blank.
Phone: 03 3344-5111
Note the information you used somewhere so you will not forget.
Click "Create Apple ID".