Expert Column: A Restful Pause in the Rainy Season — Daily Yojo with a Fermentation Bath

By Prof. Kazunori Ito
Professor, Faculty of Acupuncture and Moxibustion, Meiji University of Integrative Medicine / Director, Japan Enzyme Bath Association

Every month, Hakkou Ningen and Prof. Kazunori Ito publish a column on the enzyme bath — also called a fermentation bath — from the perspective of Eastern medicine and yojo, the Japanese tradition of everyday self-care. This is the English version of the June column, written during tsuyu, Japan’s early-summer rainy season.

It’s not only the weather

The damp, gray days of Japan’s rainy season often leave both mood and body feeling a little heavy, and it is tempting to put it all down to “the weather.” In fact, though, the way we feel at this time of year often has less to do with the humidity itself and more to do with a daily rhythm that easily slips out of balance.

In Eastern medicine, the body is thought to stay in balance when it flows with a steady rhythm. Keeping a regular daily routine is a little like keeping a car engine running efficiently. In the rainy season, when the weather makes us want to move less, gently settling the flow of the day may be the simplest way to get that natural flow going again.

Small things you can do every day

• Let in the morning light. Even on rainy days, open the curtains when you wake up and take in a little daylight. Even under a cloudy sky, light is said to gently switch the autonomic nervous system into “morning mode.”
• Take small breaks from sitting. It is easy to stay seated all day. Now and then, press gokoku (known in English as LI4), a point in the web between the thumb and index finger, or slowly enjoy a cup of warm herbal tea. Small habits like these can make the day feel quite different.
• Go easy on cold drinks. Not chilling the body from the inside is an important habit in the humid season.

A new habit: a fermentation bath as a restful pause

As a new habit, why not try a fermentation bath (enzyme bath) as a time to pause and rest? A fermentation bath uses the heat created as rice bran and sawdust ferment. It warms the body to the core and invites a gentle, slow sweat.

When we are tense, it is as if we keep pressing the accelerator — the sympathetic nervous system. The warmth of the bath is said to help the body shift naturally to the brake — the parasympathetic nervous system — so that a flow that had slowed down can begin to move again, little by little.

A few times a month is plenty. If you decide in advance, “Today is my fermentation bath day,” it can become an anchor for your body’s rhythm, and a moment to look after yourself even in the middle of a busy life.

If you have a medical condition, or on days when you don’t feel well, please don’t push yourself, and talk to your doctor first.

Weaving yojo into everyday life

Yojo is not about making a special effort on special days. It is a culture of quietly weaving care into everyday life. Don’t try to keep it up perfectly — do what you can, when you can. Spending the rainy season at an easy pace, with a comfortable pause in a fermentation bath at its center: those small steps, added up, are the first step of yojo toward getting through the rainy season feeling well. This year, why not settle into the season at your own rhythm, without overdoing it?

This column shares general ideas from Eastern medicine and the Japanese tradition of yojo. It is not medical advice, and experiences vary from person to person. The original column was written in Japanese for the Japan Enzyme Bath Association.

About Prof. Kazunori Ito

Prof. Ito is a professor in the Faculty of Acupuncture and Moxibustion at Meiji University of Integrative Medicine in Nantan, Kyoto, and a director of the Japan Enzyme Bath Association. He has spent many years in research and education in Eastern medicine, and works with Hakkou Ningen on joint research into the enzyme bath and on academic conference presentations.

Bringing the enzyme bath to your country

Guests come back to the enzyme bath for the experience itself: deep, enveloping warmth that comes only from fermentation, the scent of wood and rice bran, and a one-to-one welcome from staff. At our own shops in Japan, around 90% of guests return — yet outside Japan, an authentic enzyme bath is still rare.

It is also a business that cannot be started just by buying tubs and materials. The heat comes from living microbes, and fermentation shifts with the climate, the building, the materials and the season. When it is not managed well, the bath will not warm up, odors appear and guests stop coming. That is why learning from people who actually run enzyme baths matters.

Hakkou Ningen has supported more than 80 enzyme bath openings across Japan — from snowy Hokkaido to subtropical Okinawa — and we are now preparing our first overseas shop in Los Angeles. You train hands-on for 7 days in a working shop in Miyama, Kyoto, and we can help you set up fermentation in your own climate, with materials shipped from Japan (where quarantine rules allow) or sourced locally. Our baths are known for their low odor — we have installed them in hotels, salons and even apartment rooms, and none of the shops we have supported has had to close because of odor. It is not a franchise: you open under your own name. And through our work with Prof. Ito, we keep studying the enzyme bath together with a Japanese university.

Thinking about offering an enzyme bath in your country? Message us on WhatsApp to get our free program guide — pricing, a business simulation and the full training curriculum — or visit our opening program page.