
Quick answer
Kurokawa-sō's signature, in the Spa Association's own listing words, is a wide, deep rotenburo facing the Byōbu-iwa (屏風岩, "folding-screen rock") cliff — the most distinctive natural bath backdrop among the demand-proven Kurokawa inns.
A fuller guide to this inn — its baths, rooms and how to book — is in preparation and will follow.