Terume is a classic sento experience. All of the signs, murals, tile work is points to this being a part of Osaka's culture and history. An outstanding example if not the best. Where to start. Terume has the best steam sauna I've been in. They fill it with fragrances that change three times a week. Unlike some other steam saunas this one feels very hot. Sweating out in there has to be good for you.
The normal baths are anything but. Well built and used they feel like a good pair of jeans that you've had for a long time. Not to mention they are filled with filtered spring water. There are two different electric baths in the back along with a jet bath. These baths are filled with normal heated water. Most of the men sit in and around these baths and watch the large screen TV.
There are two hot spring baths, one is in a grotto with a mural of an Asian scene to the side of the main bath area. The second, and better of the two, is in the large rotenburo area in the back. This big shallow bath is divided into two levels. The shallower of the two set up with sleeping baths. There is also a well designed miniature Japanese garden in the back. These are straight hot spring baths no heating, watering down or recirculating. They are treated with chemicals for health reasons.
Speaking to the quality of the spring. Hot springs sometimes have a smell to them. Terume has the best smell of any spring. It reminds me of some of my favorite springs back in the USA. The more than adequately hot sodium-chloride onsen gives you a fresh and relaxed feeling. If this isn't enough, Terume has a basement with even more baths, two showers, more washing places, and another TV. Above the baths on the second floor there's a restaurant and karaoke too!
Bad things Well there's a lack of basins to use. Look around, or in the basement area for a yellow one. The other basins might be ones brought in by the customers themselves. The rotenburo is surrounded by a tall wall not allowing much of a view of anything other than the sky above. The changing area is a bit small also. These are not big complaints but good to know.
Terume Tatsumiya. Highly recommended.