Mount Iō (Yatsugatake)

Mount Iō (硫黄岳) is a mountain on the border of Chino and Minamimaki, Nagano Prefecture, Japan. This mountain is one of the major mountains of Yatsugatake Mountains. Mount Iō literally means, sulphur mountain.

Outline
Mount Iō is a stratovolcano in Southern Yatsugatake Volcanic Group, with sharp cliffs on both the northern and southern side. This mountain belongs to the Yatsugatake-Chūshin Kōgen Quasi-National Park.

In 100 Famous Japanese Mountains, Kyūya Fukada mentions the loss of a younger climbing mate, Kyoichi Yoshimura, who fell to his death while descending the northern cliffs of Mt Iō. The incident happened when Fukada was a student at Tokyo Imperial University.

Mountaineering
This mountain is one of the major mountains in the Yatsugatake Mountains, and is considered an easy climb for most climbers to reach to the top. The summitt is accessible year-round but winter speciality climbing gear is necessary from October through April.

One of the easiest routes is from Sakuradaira (櫻平), 1894 m, and takes approximately 6 hours. From Sakuradaira, the climb is approximately 5 km, and passes Natsusawa Kosen (夏沢鉱泉), 2054 m, a mountain hut with hot spring that is open year-round, O-ren Hut (オーレン小屋), 2316 m, a seasonly-opened mountain hut, and Natsuzawa Pass (夏沢峠), 2423 m. Sakuradaira is accessible by car, or by shuttle from Chino Station if staying at one of three mountain huts in the Iodake Sanso group, Iodake Mountain Hut, Natsusawa Kosen, Neishi Mountain Hut.

A second route is from Honzawa Onsen (本沢温泉), 2100 m, to Natsuzawa Pass. It is also possible to climb from Mount Akadake, the only 100 Famous Mountain in the Yatsugatake Range.

Access

 * seasonally from Minotoguchi or Tatsunokan Bus Stop of Alpico Kōtsū from Chino Station
 * Sakuradaira (car parking available)