Bathing is very important in Japanese culture. The Onsen or sento is the place to do this. While private bathing is growing, the bath is a public experience. The volcanic nature of Japan has allowed readily available hot warm.
Bathing traditionally has been with mixed sexes, but law now allows separation. relaxation and conversation are open parts of this process. You meet people and can just be along to think/mediate, too.
The process is to clean yourself first, then use the bath to soak and meditate or talk. One talks with relatives, friends, or just those present.. The social class rules are suspended as the bath is a meeting zone for people of all classes. One is to clean and purify the body to communicate with the gods who rest in nature. These two processes are separated. To enter the bath to clean like we do would be a social error in Japan.
The water must be hot. Temperatures are in the range of 105 or more so the skin gets red.