The main purpose of taking a bath, besides cleaning your body, is relaxation at the end of the day. The bathroom in a typical Japanese home consists of two rooms, an entrance room where you undress and which is equipped with a sink, and the actual bathroom which is equipped with a shower and a deep bath tub. The toilet is usually located in an entirely separate room.
Taking a bath at a Japanese home is very similar to taking a bath at an onsen (hot spring) or a sento (public bath). When bathing Japanese style, you are supposed to first rinse your body outside the bath tub with the shower or a washbowl. Afterwards, you enter the tub, which is used for soaking only. The bath water tends to be relatively hot, typically between 40 and 43 degrees.
After soaking, leave the tub and clean your body with soap. Make sure that no soap gets into the bathing water. Once you finished cleaning and have rinsed all the soap off your body, enter the bath tub once more for a final soaking. After leaving the tub, the water is usually left for the next member of the house. It is to keep the bath water clean for all members of the house that washing and rinsing is done outside of the actual bathtub.
Modern bath tubs can be programmed to be automatically filled with water of a given temperature at a given time, or to heat up the water to a preferred temperature.