Kawanaka Onsen Kadohan Ryokan

Kadohan Ryokan is a lone inn on the bank of the Ganga-sawa stream, a tributary of the Agatsuma River, near the scenic Agatsuma Gorge in Higashiagatsuma Town, Gunma Prefecture. It is renowned as one of Japan's Three Great Beauty Hot Springs, alongside Ryujin Onsen in Wakayama and Yunokawa Onsen in Shimane. Legend holds that a retainer of Minamoto no Yoritomo discovered the spring in the Kamakura period, and because the water wells up from the bedrock of the streambed, it came to be called Kawanaka, meaning 'in the river.'

The water is a calcium-sulfate spring (hypotonic, alkaline), drawn from a source named Bijin-no-yu, the 'beauty spring.' It emerges at 34.6 degrees Celsius with a mildly alkaline pH of 8.6 and a flow of about 64 liters per minute. The lukewarm water is colorless, clear, and smooth on the skin. Because the source runs cool, the main bath is gently heated, while the medicinal and source baths are served unheated as free-flowing spring water, said to leave the skin remarkably soft after a long soak.

The inn has just ten guest rooms. Alongside gender-separated indoor baths, it offers a mixed-bathing main pool and an open-air bath facing the Ganga-sawa stream, with reserved women-only hours. Day-trip bathing is not offered; the baths are for overnight guests only, with rates from 16,500 yen per person including two meals. The kitchen is known for iwana (char) and local country cuisine. Free Wi-Fi is available and the inn is open year-round.