Nyuto Onsenkyo Ganiba Onsen

Ganiba Onsen is a single-inn hot spring standing in the Sendatsuzawa national forest at the foot of Mt. Nyuto in Semboku City, Akita Prefecture, within Towada-Hachimantai National Park. The spring is said to have opened in 1846 and served for generations as a toji (curative bathing) retreat used by farmers during the off-season. Its name comes from a nearby stream about 40 metres east of the inn, where freshwater crabs (gani) were once caught in abundance. In October 1967 it was designated part of the Nyuto Onsenkyo National Health Resort Hot Spring Area, alongside Tsurunoyu, Taenoyu, Ogama, Magoroku, Kuroyu and Kyukamura.

The inn owns several of its own sources and feeds a different water to different baths. The Karako source, which supplies the mixed-gender open-air bath Karako-no-yu, is a simple sulphur spring at pH 8.1 and 49.8C, flowing at 121.7 litres per minute. The women-only open-air bath Hinazakura and the indoor baths draw on the Ganiba sulphur source (simple sulphur spring, pH 8.3, 50.2C), while the wooden indoor bath receives the Ganiba source, a simple thermal spring at pH 8.3 and 42.9C. Every bath is served entirely by free-flowing spring water with no added water, no reheating and no recirculation. The water is colourless and clear, unusual within Nyuto Onsenkyo, and is valued for its soft feel on the skin.

There are two indoor baths for men and women separately: a rock bath with a hinoki-cypress reclining pool, and a wooden bath built from Akita cedar. About 50 metres from the main building, deep in a virgin beech forest, lies the mixed-gender open-air bath Karako-no-yu, reserved for women from 19:30 to 20:30. A women-only open-air bath, Hinazakura, is also available. Day visitors may bathe from 9:00 to 16:00 for 800 yen per adult; since 1 February 2024 day bathing is suspended every Wednesday. Free parking is available for 20 cars.