Nice onsen conveniently located near Nishiarai Station. The water is, I believe, sodium based (as opposed to sulphate, etc.). The men's and women's sides are quite different, and I wish that they alternated the sides more frequently then they currently do. As it is now, they change only on every fifth day. On the women's side, there's a salt bath (but you have to bring your own salt, unfortunately), three tsuboburo, steam room and a kind of "silk" bath, which is nice. On the men's side, there are the jet baths and flat rocks. Sauna, rotenburo and regular indoor bath on both sides. There are several massage services and a large relaxation area upstairs (but there's always someone who's snoring). If you go in the afternoon, the gym on the fifth floor may be running some aerobics class, the music for which makes enough noise to diminish the peace and quiet you'd expect to get in the rotenburo. It's not too bad, though. But if you go late in the evening, say at 9 p.m., it's dead quiet and really nice. Great on a Friday evening after a long week. There is a restaurant in the spa, but in my opinion it's just OK. It costs money to park your bike; but get a receipt from the machine when you park your bike and give that receipt to the person at the counter in the spa (when you leave). The spa will give you a ticket that validates your bike parking. Generally, well worth visiting, especially if you live in the area.