Kiyashiki Onsen (樹やしき)
Address:
Kurokawa, Kumamoto, Japan
0967-44-0326
Category: Onsen
Entrance: 500円
Tubs: 1 Outdoor men's, 2 outdoor women's, and one outdoor mixed.
"There are two series of baths - one of the left side and one of the right side - which eventually lead to a mixed rotenburo at their ends. One side is for women, and the other for men; however, the attribution changes in the early evening, so you probably will try both sides if you overnight in this ryokan. The left side consists of one outside baths: a very small one plus another one which is so deep that you can stand in it. The right side is more interesting, with an inside bath and a outside one. The konyoku is the largest bath: there is a small waterfall, and stones to sit just under it."
source: Secret Onsen
Kurokawa Area Official Onsen and Ryokan Website (japanese)