Takegawara Onsen is the “have to” spot for Beppu. People always claim Dogo Onsen to be the onsen from “Spirited Away” but in my mind this is the real deal. Dogo is very touristy, Takegawara is real. Despite being such a tourist attraction it’s still just ¥100 to get in. This is as real as you can get. The water is piping hot and a pleasure to get in, even if it takes a few minutes. In the summer a short bath with many breaks is the order of business. There is also an Ibusuki style sand bath on the site for ¥1,000 but I didn’t try it. All three baths, the men’s, women’s and mixed sand bath are all from different springs (!?). If you make your way to Beppu, you’ve got to try Takegawara at least once. Seriously, why would you go to Beppu for any other reason?
Update September 2018: Had a fun chat with a local here as we laughed at two Korean boys that were clueless about using the baths. When I first went to Beppu, there were so few foreign, and especially, asian tourists. It is a different experience now and the famous places like Takegawara have seen an increase of use.