AT A GLANCE
Why go?
Fudō-iwa (不動岩, "the Immovable Rock," also marked 不動岳, Fudō-dake) is a tooth of sheer grey rock that juts from the high ridge of Mt. Hotaka / 上州武尊山 (2,158 m), one of Japan's 100 Famous Mountains, on the border between Katashina village in Gunma's Tone District and the towns of Kawaba and Minakami. Reaching it means earning it: the approach is a long, stiff climb up an old mountain-worship ridge, and the rock-peak itself is a short, exposed scramble studded with fixed chains and a couple of truly narrow squeezes.↗
For hikers it is the emotional climax of the route between the Katashina/Hanasaku side and the summits of 前武尊 (Mae-Hotaka) and 武尊山 — a place where the trail briefly stops being a path and becomes a rock climb with views down into forested valleys and out toward the Oze highlands. For all its drama it stays compact and reversible: there is a bypass around the peak for anyone who would rather admire the rock from below than climb it.
A sacred peak in mountain-worship country
Mt. Hotaka has long been a spiritual mountain, and the trail to Fudō-iwa is threaded with evidence of centuries of shugendo practice and lay pilgrim societies. On the Katashina (Hanasaku) approach you pass stone lanterns and koshintō steles inscribed with dates from around 1800, carved images of Yakushi and Bodhidharma, and weathered statues of Fudō Myōō himself — the Immovable Wisdom King whose name the rock carries. Records along the ridge credit the ascetic 普寛行者 (Fugen Gyōja) with opening the mountain at the close of the 18th century, and bronze figures of the legendary prince Yamato Takeru stand watch on 前武尊 and near the summit.
