Mixed bathing is the oldest form of the Japanese bath, and it is dying out. Not because of a law, and not because of any new modesty, but because a handful of men turned these pools into hunting grounds. Here is what remains, how it works today, and why it is worth seeing before the last one closes.
My first time was at Tsurunoyu, in October snow, in Akita. A milky outdoor pool, water so opaque it hides everything ten centimetres below the surface, old men discussing the weather and couples not looking at each other. Nobody makes anything of it. I had spent twenty minutes working out how I was going to handle the situation, and the answer turned out to be that there was nothing to handle.
That is roughly what everyone discovers on their first try. Which is why the disappearance of mixed bathing strikes me as a real loss rather than a modernisation.
What a konyoku actually is
A konyoku is an onsen pool where everyone bathes together. It was not a curiosity, it was the default. Japanese public baths were mixed for centuries, and it was Western diplomats in the Meiji era who took offence, and then the government that legislated in order to look civilised to foreigners. Separating men and women is not a Japanese tradition. It is an import.
What survived is almost entirely rural: mountain hitō and old inns. Almost never in a city, almost never in a modern hotel. The geography of mixed bathing is the geography of the emptying countryside.
It is also worth saying what it is not. It is not a pickup spot, it is not risqué, and the atmosphere is considerably less charged than a municipal swimming pool back home. People come for the hot water.
Why they keep closing
The reason is simple and unpleasant. The Japanese call them wani, crocodiles: men who settle into the pool for hours, motionless, nose just above the water, waiting for a woman to come in. Some park themselves directly outside the women’s changing room. A Japanese lawyer who specialises in hot springs, and who has visited close to three thousand of them over thirty years, describes the behaviour as routine.
The outcome was predictable. Women stopped coming, the mixed pools filled up with men waiting for women who no longer came, and the inns eventually partitioned them or closed them. Modesty did not kill the konyoku. A minority made the place unlivable for everyone.
I am saying it plainly because most writing on the subject talks around it, and a woman reading this is entitled to know what she is walking into.
The rules, and the one that changed recently
You wash completely before getting in, sitting on the little stool, as everywhere. You go in naked unless told otherwise. The small towel never touches the water: it goes on your head or on the rim. No photographs, ever, and that rule is stricter here than anywhere else.
The recent change concerns children. The Ministry of Health lowered the mixed-bathing age limit from around ten to around seven, and the prefectures amended their ordinances accordingly. In Tokyo, the rule has applied since 1 January 2022. The catch is that each prefecture decides for itself, so the age still varies from place to place. Travelling with a seven or eight year old, ask locally rather than assume.
One last rule, unwritten but decisive: do not linger. Get in, relax, get out. That is precisely the opposite of crocodile behaviour, and it is what instantly marks you as an ordinary bather.
Yuamigi, the fix that works
Rather than close, some places decided to dress everybody instead. A yuamigi is a thin cotton tunic, supplied on site, worn in the water.
The most interesting experiment took place at Sukayu, in Aomori, whose thousand-person bath is one of the most impressive in the country. In November 2021 the inn trialled yuamigi for everyone, men included, over five days. The proportion of women bathing went up. It is a modest result, but it says the essential thing: women were not avoiding nudity, they were avoiding being watched.
Many places also run women-only slots, usually in the early evening. If you are a woman and it is your first time, start there.
The ones I have seen
The numbers match the map above.
1. Tsurunoyu, at Nyūtō, Akita. The most beautiful, and the one I would send anyone to first. The water is an opaque white that settles the modesty question by itself, the thatched buildings date from a time when the lords of Akita came here to take the cure, and winter there is spectacular. I wrote a whole piece about it.
2. Takaragawa, at Minakami, Gunma. The largest, and the most photographed in Japan. Huge terraced pools along a river in a wooded gorge. Gorgeous in autumn and frankly unreal under snow. It is also the busiest on this list, so the least intimate.
3. Hoshi Onsen Chōjukan, Gunma. One valley over. The bath is a Meiji-era timber hall with arches, high windows and river pebbles on the floor of the pool, through which the water rises. It looks like a chapel. It is probably the finest space on this list.
4. Awanoyu, at Shirahone, Nagano. A bluish-white sulphur water in a valley of the Japanese Alps. The outdoor pool is wide and shallow, the water milky, and the place has a particular softness in late afternoon.
5. Shikinejima, in the Izu islands. The odd one out. Stone pools at the edge of the sea, free, open day and night, and you go in wearing a swimsuit. It is by far the easiest way to start if the idea makes you nervous, and the whole island is worth the trip.
One word of caution: arrangements change often. A mixed pool becomes women-only, a time slot moves, an inn starts requiring yuamigi. Check the establishment’s own site before driving two hours.
Going for the first time
Pick opaque water. That is the only advice that really matters. Milky, sulphurous or iron-rich water settles in one second what three paragraphs of mental preparation will not.
Go early morning or mid-afternoon, never Saturday evening. Stay the night if you can, because inn guests often have the baths to themselves once the day visitors have left, and that is when the place goes quiet.
And if you walk in and do not like the feel of it, walk out. Nobody will mind, nobody will notice, and in almost every case there is a separated pool next door.
If the subject interests you, read also the rules of the Japanese bath, which apply everywhere, and my pick of the best onsen in Japan.