Most Japanese homes have a deep tub, and on winter evenings most people use it. This is how the home bath works, and how to take one in a British bathroom.
I grew up taking a bath after dinner, hot water up to the chin. Japan does the same, only more seriously.
As Japanese homes got their own baths after the war, the bath makers sold the idea with one line: 遠くの温泉より我が家で温泉気分. Better the feel of a hot spring at home than a hot spring far away. It still holds. The trip to the springs is the treat. The bath at home is the habit.
Wash first, then soak
In Japan you wash before you get in, sitting on a low stool outside the tub. The bath is for soaking, not cleaning. Because the water stays clean, many families share one bath through the evening, with a lid on to hold the heat.
In a British bathroom, shower first, then run the bath. Before you get in, pour a few jugs of bathwater over your shoulders. At the springs this is called kakeyu (かけ湯). It lets you meet the heat gradually.
How hot, and for how long?
About 40°C, for about ten minutes. When the water-heater maker Rinnai asked 50 people in each of Japan's 47 prefectures, 40°C was the most common answer, and 10 to 14 minutes the most common soak. Japan's Consumer Affairs Agency suggests 41°C or below, and no more than ten minutes in the water. A bath thermometer takes out the guesswork.
Sink to the shoulders. Don't read. Don't scroll. Do very little.
What do Japanese people put in their baths?
Often, something. Japan has made bath additives, nyūyokuzai (入浴剤), since 1897, when Tsumura sold Yokuzai Chūjōtō, made from the leftovers of a herbal medicine. Bathclin followed in 1930. Kao's carbonated tablet, Bub, arrived in 1983. A Japanese chemist now carries shelves of them. Most fall into three families:
- Mineral soaks, made in the character of a spring: chloride, alkaline or carbonated. See the onsen waters
- Herbal baths: yuzu on the winter solstice, shōbu leaves in May, and blends from the old medicine chest. See herbal baths
- Cooling baths for summer, made with Japanese mint. See cooling baths
Then there's yunohana (湯の花), the mineral flakes gathered from the springs themselves. The nearest thing to a real spring you can bring home.
After the bath
There's a word for the time just after: furo agari (風呂上がり). Wrap up in a towel that drinks water fast. Have a glass of water, or a cup of hojicha, roasted green tea. Then keep the evening quiet.
Little and often
Tōji, the old hot-spring cure, was never a single bath. People stayed at the springs for weeks and bathed several times a day. The home version works the same way. One bath is pleasant. A bath most evenings, through the winter, is the practice.