MOMIJI HOT-SPRING is a newly opened hot spring wing at Karuizawa Prince Hotel West, primarily for hotel guests with limited day-use by non-guests permitted. It is an upscale spa space featuring an indoor bath with large glass windows overlooking seasonal nature and an open-air bath that showcases vivid autumn foliage. The authentic Finnish-style sauna allows self löyly, so you can work up a good sweat while surrounded by the pleasant scent of wood. A deep, continuously overflowing cold plunge bath and an outdoor cooling area where you can feel Karuizawa's crisp air let you totonou (achieve a state of perfect relaxation) in comfort.