Yu no Sawa Onsen (Akita)
- Location
- Semboku, Akita, Japan
- Water type
- sulfurous
- Temperature
- 44 °C
- pH
- 6.5
Water profile
Relaxing — deep, immediate muscle release.
Rich in active gases or metals — a strong mineral character.
Soft water — natural, classic buoyancy.
Yu no Sawa Onsen in Kitaakita City, Akita Prefecture, has undergone significant transformation in recent years—one of its two historical inns, the Soma Onsen Ryokan, reopened in July 2025 under the new name Moriyoshisan Onsen Chiisana Mori no Yu (Small Forest Waters of Mt. Moriyoshi) following a business succession, while the city-managed Moriyoshiyamazo suspended operations in 2022 and planned to reopen as simplified accommodation without spring or meal service. The spring's location near Mt. Moriyoshi—a mountain in the Shirakami-Sanchi border area of Akita—connects it to the extraordinary natural heritage of one of Japan's most pristine mountain landscapes, giving the thermal waters a setting of deep ecological and scenic value. This spring's institutional history of transformation and renewal mirrors the resilience of Japan's rural onsen tradition in adapting to changing economic and demographic conditions in the country's northern interior.