To expedite business transactions in Japan, it helps to pay with Japanese currency. Trying to pay with Korean currency causes a certain amount of confusion.
Speaking of international travelers, I think I saw more Westerners in Kyoto the first evening I was here than I did the whole time I was in Kyushu. And half of the ones I saw on Kyushu were German backpackers at Mt. Aso*. The sushi place I’ve been going to has been full of Japanese people most of the time, but last night I was there a little later and there were mostly Americans and Europeans, all going for the California roll. A really tall Scandinavian guy kept bumping his head on the lanterns.
* Of course there were German backpackers. There are always German backpackers.