Open-Air Bath Day (Roten Buro no Hi)

What is Open-Air Bath Day?

June 26th is "Open-Air Bath Day" (Roten Buro no Hi) in Japan. The date comes from a wordplay in which "ro" (6), "ten" (the dot between the numbers), "bu" (2), and "ro" (6) combine to sound like "rotenburo" (open-air bath). It was established in 1987 by the Yubara-cho Ryokan Cooperative and the Yubara Tourism Association of Yubara Onsen, a hot spring resort in Maniwa City, Okayama Prefecture. The day expresses gratitude for hot springs and aims to spread the appeal of bathing outdoors in nature. Yubara Onsen held the first "Open-Air Bath Day" event in Japan on June 26, 1987, and has continued to hold it on this date ever since.

Yubara Onsen and its "Sunayu"

Yubara Onsen is a hot spring resort along the Asahi River in northern Okayama Prefecture. Its symbol is "Sunayu" (sand bath), an open-air bath that wells up from the bed of the Asahi River.

• Origin of the name: it is called "Sunayu" because the hot water springs up from between the sand on the riverbed
• Free, 24 hours a day: apart from cleaning times, it is known as an open bath that anyone can use free of charge
• "Yokozuna of the West": in a ranking of Japan's open-air baths modeled on sumo rankings, it was placed as a "yokozuna" (grand champion) of the West
• A view of the dam: Sunayu sits just downstream of Yubara Dam, offering the unusual view of a dam towering above bathers

Events timed to "26"

At Yubara Onsen's Open-Air Bath Day events, programs have even been scheduled at 26 minutes past the hour.

• 6:26 a.m.: the "Oyutori" hot-water drawing ceremony
• 7:26 a.m.: a big cleanup of the open-air bath (Sunayu), signaled by a conch shell
• Around 9:26 and 10:26 a.m.: a hot spring thanksgiving gathering, taiko drumming, a morning market, and more
• From 11:00 a.m.: free access to the indoor baths of local inns and hotels

Programs and times may change from year to year, so check Yubara Onsen's official information before visiting.

Fun facts about open-air baths

• What "roten" means: "roten" means outdoors with no roof. A bath taken under the open sky is a "rotenburo," and rustic baths set in nature are sometimes called "notenburo" (field baths).
• When the river itself is a hot spring: like Yubara's Sunayu, open-air baths that use hot water springing from riverbeds and riverbanks can be found across Japan, letting bathers enjoy the river up close.
• Bathing safely: open-air baths are affected by the season and weather. In summer, drink water to avoid overheating and dehydration, and get out of the water right away if you hear thunder.
• Etiquette: the same basic manners apply as indoors—rinse off before getting in, and keep your towel out of the water.

Ideas for spending Open-Air Bath Day

• Visit a nearby hot spring or a public bathhouse with an outdoor bath area.
• Put your phone away and take some time to gaze at the sky and scenery while you soak.
• Look up the water type and history of a hot spring before you go.
• Research Yubara Onsen's Sunayu and other famous open-air baths as ideas for your next trip.

A uniquely Japanese pleasure: soaking under the open sky

June 26th is a day to rediscover the appeal of enjoying hot springs outdoors. This anniversary, which began at Yubara Onsen with its "Sunayu" springing from a riverbed, reminds us of the Japanese scenery created by nature and hot springs. On a sunny day between the rainy-season showers, why not take a slow soak under the open sky?