How to Enjoy Gunma’s Onsen

Japanese people have bathed and relaxed in naturally occurring hot springs since ancient times, believing them to aid in recovery from injury and illness.

As onsen facilities became popular tourist destinations, the Hot Spring Law was introduced in 1948 to define the differences between onsen and regular baths. According to the law, an onsen must be natural hot water discharged from an underground source at over 25 degrees Celsius and must contain certain naturally occurring minerals.

The symbol that identifies onsen on maps, a partial circle with three wavy lines rising vertically like steam, was developed at Isobe Onsen in the 1600s. The symbol is used on maps around Japan today.

While the specific health benefits of bathing in mineral-rich onsen waters may be difficult to feel immediately, the relaxation effects are obvious. Nothing soothes tired muscles like a hot soak after a day of hiking or skiing. Most onsen waters contain naturally occurring minerals such as sulfur (at Kusatsu Onsen), iron (Ikaho Onsen), or chloride ions (Shima Onsen). Such minerals are said to be beneficial for different health conditions, ranging from joint stiffness to high blood pressure. Taking a bath a few hours before bed is believed to promote deeper sleep, and bathing in hot water increases blood circulation. Even the experience of greater buoyancy in a hot bath takes the stress off joints.

Water temperatures are typically around 40–45 degrees Celsius, which can feel very hot to first timers. Until you become used to the hot water, it’s a good idea to keep the bath time short—no more than 10 minutes at a time—with breaks to cool down.

Yes, you will be naked. No, people will not be looking at you. Men and women bathe separately at onsen (there are some exceptions when mixed bathing is allowed. These usually require bathing clothes or towels). The first step is to make sure you enter the correct side of the baths, so it’s a good idea to check the Japanese characters for “man” (often with a blue curtain) and “woman” (often with a red curtain). For daytime bathing, you generally pay a fee as you enter, and will be given a larger towel for drying and a smaller towel to take to the bathing area, for washing. It’s a good idea to remove glasses, watches, and jewelry that may become discolored by the mineral waters. Leave your clothes and the larger towel in a locker or basket and enter the bath area.

Many onsen prohibit patrons with tattoos. Traditionally, tattoos have been associated with organized crime in Japan. Most Japanese people are tolerant of tattoos on foreign tourists, however, they still make some people uncomfortable, so some onsen proprietors ban them entirely. If you have a small tattoo, it may be OK to cover it with a bandage. Check with the onsen before you visit, as more and more are accepting visitors with visible tattoos."

Onsen baths are for relaxing, not for washing, and they are used by many people each day. It is important to wash your body before you enter the bath, to keep the water clean. There is usually a row of low stools with hand showers near the baths, as well as supplies of soap and shampoo. Take your time to get clean using the showers, and be sure to rinse the stool and wash-bucket after you finish. As you enter the bath, make sure your hair and your small towel do not touch the water. You might see other bathers fold the towel up and place it on their heads to keep it cool.

Running, splashing, and swimming will disturb the relaxed atmosphere of the bath, but conversation is the norm; the onsen is a communal and social space. After relaxing in the bath, use the small towel to dry off a little so you don’t drip water in the changing room.

Please note that you cannot use cameras or phones in changing areas or onsen.