Welcome to Kurokawa Onsen
It's well worth an overnight in Kurokawa Onsen for a relaxing stay, but for day trippers a nyūtō tegata (onsen passport; ¥1300) allows access to three baths among the town's 24 ryokan (open 8.30am to 9pm). Buy the pass at the tourist information desk and ask which locations are open during your visit.
Favourite baths include Yamamizuki, Kurokawa-sō and Shimmei-kan, with cave baths and riverside rotemburo (Kurokawa is especially famous for its rotemburo). Many places offer konyoku (mixed bathing) alongside women-only baths.