OU Land is the biggest day use bath in the Kaike Onsen area and the most supersento like. There is a hotel connected to the baths, but it seemed that a large number of users here were locals just coming for a soak. I did not actually use the normal baths here but used one of their many family baths as I was there with my wife and daughter. Family baths are really fun now a days because my daughter has gotten too old to go into the men's side with me. The cost of a family bath starts at ¥1,700 for 60 minutes. They can be busy and booked out but we were very lucky and arrived just as one opened up. The family bath we had was the most basic with a single large stone tile lined bath looking out on a mini walled off garden.The changing room was big enough for the three of us to move around in had a sink and places to put your clothing. The bath was filled from two taps, one with straight extremely hot Kaike onsen spring water (be careful) and some cold municipal or well water to cool. You could adjust the temperature of the bath on your own by adjusting the flow coming from these taps. A great experience at a very reasonable price. Definitely the best option for families and young children in Kaike.
About the spring, Kaike is extremely hot coming from the ground, has a saltwater smell and taste to it and is outstanding. One of the best extremely hot springs in Japan.