Tsukioka Onsen — Bijin no Izumi (月岡温泉 美人の泉) 月岡温泉 美人の泉
Emerald green from the sulphur: water at 51°C, among the most sulphurous in Japan.
Tsukioka Onsen, in the municipality of Shibata, is known throughout Japan for the emerald-green colour of its sulphurous water, among the most concentrated in the country. The Bijin no Izumi daytime public bath lets you try it without booking a night at one of the area's ryokan.
Niigata
川崎, 月岡カリオンパーク入口
https://theanimetrip.com/luoghi/tsukioka-onsen-bijin-no-izumi