Murodō: walking at 2,450 m室堂

A crater pond about 631 m round and 15 m deep, with Mikurigaike Onsen on its shore (visible in the photo) and Mount Okudainichi behind. On a still morning it mirrors the ridge, as in the hero photo from mid-October. In spring it is ice-covered, and in early summer it can still hold floes. A stone path circles it, so trainers are enough in dry weather; in October it can be wet or frosted.

Billed as Japan's highest onsen. Day visitors bathe for ¥1,100 (adults) or ¥800 (children), 9:00–16:00. The water is milky white, acidic and smells of sulfur; the lodge reports it as free-flowing with no added water or heating, and its heat comes from the volcanic steam of Jigokudani. There is a café at the lodge too (8:30–16:30). Overnight guests can bathe through the evening and morning.

A crater of yellow sulfur and steaming vents, the reason the lodges have hot water. The walkway through it has been closed since fiscal 2012 because volcanic gas and vent activity raised the risk of poisoning. The operator's notice of 13 February 2020 repeated the closure and asked walkers to take care between Enma-dai and the Dainichi lookout, where the gas can thicken with the wind. Look from the lookouts, read the signs, and do not step off the path. A wet cloth over the mouth is the standard advice if you smell the gas.

The rock ptarmigan (Lagopus muta japonica) is a Special Natural Monument and Toyama's prefectural bird. The pine scrub (haimatsu) around Mikurigaike, Jigokudani and Raichōzawa ('ptarmigan valley') is its habitat. The plumage is mottled brown in summer and white in winter, so in October it is part way between the two. Dawn and dusk near the lodges give the best chance; the bird is well camouflaged and often found only when it moves. Stay on the path, keep well back, and do not feed or chase it.

Past the pond the path reaches Raichōsō, on a shelf above Jigokudani, then drops to Raichōzawa, the valley with a camp site and a hut under the Tateyama ridge. Autumn colour here is in late September. It is downhill out and uphill back, so keep the climb and the last bus in mind. Raichōsō's notice of 1 October 2026 advises against the Murodō to Raichōsō route without winter equipment and knowledge from mid-October until early May: blizzards, whiteouts, hypothermia and frostbite are real risks.

Oyama is the shrine peak of the Tateyama group and the usual climb from Murodō. An easy, maintained path runs to Ichinokoshi (一ノ越, 2,692 m), then about an hour of steep, loose rock leads to the summit and the Oyama Shrine at the top. The highest point of the group, Ōnanji (3,015 m), is another 20 minutes along the ridge. The net climb from Murodō is about 550 m.

Colour peaks in mid-September on the Murodō plateau and the 3,000 m ridge, late September at Daikanbō, Raichōzawa and Jōdozawa, early October at Midagahara and Kurobedaira, mid-October at Kurobe Dam and Ōgizawa, late October at Bijodaira, early November at Tateyama Station and Shōmyō Falls. From 1 September to 31 October the Nature Conservation Centre beside the terminal (3rd floor, 8:30–17:00) hands out an autumn Mikurigaike sticker. See the autumn leaves guide and Shōmyō Falls.

Snow settles on the plateau from about late October in a normal year, and the highland-bus road from Bijodaira can see snow, ice, ploughing, delays and cancellations from then. Murodō gets about 8 m of snow in a winter. The Toyama side can be suspended for snow while the Nagano side runs, so check the operator's status page. The route runs a winter timetable from 4 November and closes on 30 November 2026. The photo shows Murodō Sansō with early patchy snow.

Murodō has no town light. After the last Toyama-bound departure (16:20, or 17:00 on peak days) the plateau belongs to the people sleeping in the lodges, which is the only way to see the sky from here. The lodges are a short walk from the terminal; take a headtorch and a warm layer, and stay on the path, because Jigokudani's gas and the pond's edge are not places to wander in the dark. Cloud decides the night; check the operator's Murodō live camera in the evening.