Just a heads up, Japanese women rarely uses Tinder for hook ups - I went there a couple months ago and had several hookups during my stay there. I would say, if you want it easy, Soaplands are the way to go, a big plus if you can speak Japanese. If you’re in Osaka, there’s also Tobita Shinichi (this is mostly popular as the girls there are very pretty and seemingly in their 20s tho a bit expensive compared to others and they don’t do shower) and Matsushima Shinichi (they got showers which is a big plus and also the women are decent but not as good as the ones in Tobita but still good). I personally went to Matsushima as I prefer more mature than me plus they got showers. In Tokyo, doing the nightlife like going to bars or clubs to meet with people seems to be the easiest from my experience especially if you speak Japanese. Just be careful of touts. If you got a Japanese friend to go with you when you’re there, the better the chances you’ll get. Those are the ways I managed to get some hookups during my trip to Japan but yeah, Tinder it will be mostly foreigners as well that will be there more as Tinder isn’t as popular over there compared to other countries I’ve been.