Oboke Iya Onsenkyo

Oboke Iya Onsenkyo is a group of five hot spring inns in the mountains of Miyoshi, in western Tokushima, between the Oboke gorge on the Yoshino river and the Iya valley. The inns promote the area together as Oboke-Iya Ittemirukai, and describe Iya as one of the three great hidden regions of Japan.

The inns and their water

Hotel Iya Onsen is known for its open-air bath on the bank of the Iya river, reached by a cable car that runs 170 metres down a cliff at an angle of 42 degrees. Its water, an alkaline simple sulphur spring, rises from the source on its own, which the Miyoshi tourism site calls rare in Shikoku. Hotel Kazurabashi, at the Yumoto Shin-Iya Onsen, has a cable car going the other way, up to an open-air bath on the slope above.

Sunriver Oboke and Oboke-kyo Mannaka stand above the Oboke gorge. Sunriver's water is a strongly alkaline simple sulphur spring of pH 9.57. Hotel Hikyo no Yu, at the Iyakei Onsen, draws on a different kind of water, a bicarbonate spring containing fluorine and metaboric acid.

The gorges and the vine bridge

The Yoshino river has cut the gorges of Oboke and Koboke through the mountains. Oboke was designated a Natural Monument in 2014 and a Place of Scenic Beauty in 2015, and Koboke was added to the scenic designation in 2018.

Iya Kazurabashi, a bridge 45 metres long woven from the vine shirakuchi-kazura (シラクチカズラ), hangs 14 metres above the Iya river and is rebuilt every three years. It is a national Important Tangible Folk Cultural Property, and legend credits it to warriors of the Heike clan who fled into the Iya valley after their defeat.