Modern-style onsen located in Komagome (Toshima-ku), known for its natural hot spring water drawn from 1,800 meters underground. The facility includes indoor and outdoor baths — including a rotenburo (open-air bath) beneath cherry trees in spring — as well as a sauna, restaurant, relaxation areas, and massage services. The atmosphere is calm, clean, and refined, catering to both locals and a few informed tourists.

Price: Around ¥1,300 on weekdays, ¥1,500 on weekends (adult fare)
Touristy? : Moderately touristy. Popular with Tokyo residents and some travelers looking for a relaxing onsen experience without leaving the city.