Yudan Onsen Yudan-no-Yado

Yudan-no-Yado is a small hot spring inn in the Yudan Onsen hamlet on the southern foot of Mount Iwaki in Hirosaki City, Aomori Prefecture, long favoured by local people as a therapeutic bathing retreat. The spring is said to have been opened in 1724 by Shibata Chobei, and the inn has welcomed toji (long-stay cure) guests for more than two centuries. The inn itself describes the site as a healing spring cherished for over 250 years. Surrounded by forest and apple orchards, it retains a quiet setting in contrast to the more developed Dake Onsen nearby.

The water is a sodium-calcium (magnesium) chloride-bicarbonate spring emerging at around 44 degrees Celsius with a pH of roughly 7.2. It is served free-flowing from the source with no added water and no recirculation, reaching the tub at a mild 42 degrees. The bath looks clear but carries a faint greenish cloudiness, a light iron scent, and a salty, slightly bitter taste, with mineral deposits built up around the spout and tub rim.

Bathing is in a single indoor tub for each gender, with no open-air bath. The tub seats only two or three people, but a full wall of windows opens onto the forest and the changing seasons at the base of Mount Iwaki. Day-trip bathing runs from 8:00 to 19:00 at about 400 yen for adults. Overnight stays cost around 9,500 yen with two meals, or from about 6,200 yen for room-only therapeutic stays. Parking is available for about 15 cars.