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Denkiburo 　
電気風呂

There was a sudden flash of lightening last night as I was putting my son to bed, followed by a low rumbling of thunder. I started telling my son how to calculate the distance from our house to the lightening strike by counting the seconds between seeing the lightening and hearing the thunder. My son was more interested in discussing what would happen if one were hit by lightening. I was explaining electrocution when I suddenly thought of electric baths or denkiburo. The electric bath is not primative variation on the electric chair, but is a regular feature at public baths in Japan. A simple kanji everyone who goes to a sento or onsen should know is denki: 電, or electricity. This kanji, when coupled with 風呂, bath, means electric bath, or denkiburo. These are tubs and pools, large and small, with electricity running through them. They are a staple at public baths or sento, and sometimes appear at hot springs resorts or onsen. Their therapeutic effects are compared to a full-body massage that increases blood circulation and they are thought to be especially efficacious for the elderly.

During my first years in Japan I rented a studio apartment in a building with shared bathrooms, No bathing facilities were expected or provided: the sento across the river was cheap and offered a variety of soaking and bathing options. I went later than usual one night and upon entering the bathing area noticed, through the steam, a large group of tattooed men relaxing in the main pool. Assuming they were from the yakuza office down the street, I looked for a different place to soak. A smaller pool off in the corner was empty. I advanced through the steam and extended a toe toward it's surface to judge the water temperature. Suddenly I was 5 feet away from the pool gyrating wildly and trying not to fall on my ass. I heard laughter and guffaws behind me. Yes, I had wandered into the denkiburo, and it had taken me by surprise. I joined the yakuza, in the main pool. They were friendly and sympathetic and asked me why I hadn’t seen the sign on the wall above the denkiburo.

I've tried the denkiburo since then. Knowing what I was getting into, I was able to sit down and stretch out without writhing or screaming. Still, the electric pulse was too strong for me, reminding me of periodic embraces of a low voltage electric eel.