Mount Nikkō-Shirane, Stratovolcano in Nikko National Park, Japan

Mount Nikkō-Shirane is a 2,578-meter stratovolcano on the border of Tochigi and Gunma Prefectures. Its summit, Okushirane, is an andesite lava dome rising from a ridge of older Neogene volcanic rock. The upper slopes are bare grey-brown rock with snow in the gullies, while dense green forest covers the lower flanks.

The volcano formed approximately 20,000 years ago and experienced several significant eruptions throughout its history. A notable steam eruption in 1649 created a new crater and left visible marks on the mountain.

The name Shirane describes peaks whitened by snow, and several mountains across Japan share it; this one is distinguished as Nikkō-Shirane, though the Geospatial Information Authority's 1:25,000 Nantai map labels it only Shirane. From the Edo period to the Meiji era, Okushirane was worshipped in Jōshū as Arayama Gongen, and faith-climbing routes left place names that survive only on maps. Today shrines stand on the summits of Maeshirane and Okushirane.

Multiple hiking trails reach the summit from different starting points, with the Yumoto Onsen Trail offering convenient bus access for visitors. Your choice of route depends on your fitness level and available time, and checking weather conditions before departure is essential.

The summit's lava dome is made of andesite, and the mountain is the highest point in both Tochigi and Gunma Prefectures. It is also the highest mountain in Japan north and east of the Kanto region, and the highest outside the Chubu region. The summit shrine, Okushirane Shrine, was completely destroyed in the 1649 eruption.