Yoshina Onsen Oyado Sakaya

Sakaya is the principal inn of Yoshina Onsen, a tiny spring hamlet on the Yoshina River at the northern foot of the Amagi range in Izu City, Shizuoka. The spring is named in the founding records of Zenmyoji temple, built in 724, which is why Yoshina is called the oldest hot spring in Izu, with more than 1,300 years of documented history. Sakaya began as a sake brewery, and in the late sixteenth century it hosted Lady Oman, a consort of Tokugawa Ieyasu, who is said to have conceived here the two sons who founded the Kii and Mito branches of the Tokugawa house. The house became an inn during the Edo period and is now run by the twenty-fifth generation of the same family.

The water is a simple hot spring, described by the inn as weakly alkaline at pH 7.6. It is clear, odourless and tasteless, and noticeably soft on the skin. Three sources feed the inn, named Oyu, Hanazawa and Susugaki, yielding a combined 425 litres per minute at 45.3, 47.0 and 65.5 degrees Celsius respectively. By adjusting how much of each source is fed into the tubs, the inn holds a comfortable bathing temperature without heating or diluting the water. Nothing is recirculated and nothing is chlorinated, so every tub runs on undiluted spring water, drained and refilled daily by the owner himself acting as yumori, the keeper of the spring.

There are six baths. The two large indoor baths are Oman-san-buro, built of hinoki with a floor of Izu stone, and Taro-san-buro, designed by the artist Taro Okamoto; they swap between men and women morning and evening. The open-air baths are Orionza-buro, facing the Amagi ridgeline, and Shirafuji-no-yu, set beneath a 200-year-old white wisteria. Two more open-air baths, Sakadaru-no-yu shaped after a sake cask and the hinoki Kodakara-no-yu, are reserved privately with no booking, no charge and no time limit. The inn has 23 rooms for about 70 guests and 50 free parking spaces. Day bathing is not offered; the baths are for overnight guests only.