Funabara Onsen Funabarakan

Funabarakan is a weathered, family-run inn standing alone beside the Funabara River gorge in Kamifunabara, Izu City, Shizuoka, along Route 136 between Shuzenji and Toi. Funabara Onsen is an old spring documented in the Edo period, when it was divided into the Ko-no-yu and Otsu-no-yu baths, and local tradition holds that the shogun Minamoto no Yoritomo bathed here. The present inn opened in 1958 and has been run by the same family ever since, calling itself Monowasure-no-yu, the bath that makes you forget.

The water is a simple hot spring, hypotonic, weakly alkaline and high in temperature, with a pH of 8.0 and a source temperature of 45.6 degrees Celsius. The inn's private source yields 150 litres per minute, enough that every tub in the building runs on undiluted, unheated, unfiltered and unchlorinated free-flowing water. The spring is piped without contact with air and enters each tub from the bottom, so the water is colourless, clear and noticeably soft on the skin.

Bathing is split between Yama-no-yu, with an indoor tub and an open-air section, the smaller indoor Kawa-no-yu, and the inn's signature private standing bath, 1.2 metres deep. Filled with water close to body temperature, the standing bath lets guests soak upright for long stretches, and the aquatic bodywork therapy known as Watsu is offered there. Day bathing runs from 12:00 to 15:00 by reservation at 800 yen for adults, or 1,500 yen including the standing bath. The inn has 14 rooms and serves hearth-grilled game and river fish at dinner.