A couple things to note. The Japanese eShop is, not surprisingly, entirely in Japanese, but it's laid out exactly like the North American and European eShops. All prices are in yen, but certain foreign credit cards will actually work perfectly fine (you'll have to try yours out to see if your credit card provider allows it), though you may have to pay a currency conversion fee. You can also purchase Japanese eShop cards from certain retailers, though that also comes with its own unique quibbles. Also, games you purchase with your Japanese account can be played with any account, with the exception of DLC, which is only accessible by the Japanese account.