Sukayu Onsen

Sukayu Onsen is a historic hot spring resort situated high in the Hakkoda Mountains of Aomori Prefecture, on the northern island of Honshu, Japan. It sits at an altitude of nearly 900 meters, making it famous for its heavy, deep snowfall during the winter months. It is easily accessible via the Mount Hakkoda Ropeway and is a popular destination for hikers and skiers.

The Sen-nin-buro, which translates to "bath of a thousand people," is the main attraction at Sukayu Onsen and is the largest mixed-gender bath in Japan. It is a massive, historically preserved wooden bathhouse featuring several interconnected pools of varying temperatures. The iconic structure is built entirely from smooth Japanese cypress wood.

The water at Sukayu Onsen is a highly acidic, sulfuric hot spring known for its strong, distinctive smell of rotten eggs. The water temperature is quite hot, and the mineral content is believed to be highly therapeutic for skin conditions, hypertension, and nerve pain. The milky blue water is invigorating but requires bathers to acclimate slowly.

Yes, the famous Sen-nin-buro is traditionally a konyoku (mixed-gender) bath, meaning men and women bathe together in the same large pool. To accommodate this, the bathhouse requires women to wear a special modesty wrap called a yugi, while men wear a fundoshi (loincloth). Recently, the facility has also introduced specific women-only hours to provide more privacy.