Oze no Koya Mountain Hut, also known as Ozenuma Lodge, is a mountain refuge and basic accommodation facility within Oze National Park, situated at the edge of Ozenuma Pond in the Katashina-mura area of Tone District, Gunma Prefecture. Oze National Park straddles the borders of four prefectures—Gunma, Niigata, Fukushima, and Tochigi—and encompasses Japan's largest montane wetland at an elevation of approximately 1,400 metres. The park is designated a Ramsar wetland site and is nationally celebrated for its summer carpet of Asian skunk cabbage (Lysichiton camtschatcensis) and fields of Japanese cotton grass.
The mountain hut is one of several lodges within the Oze wetland, accessible only by foot along maintained trail systems from multiple trailheads: Hatomachi-toge, Oshimizu, or Fujimi-Shita, with approach times of 2–4 hours depending on the entry point. No road vehicle access is available to the hut. The facility operates seasonally from late May through late October, corresponding to the period when the Oze trails are clear of snow and the wetland ecosystem is at its most accessible and biodiverse.
Accommodation is in dormitory-style tatami sleeping arrangements or, in limited quantity, small private rooms. Bedding is provided; sleeping bags are not required but the rooms are basic and guests should expect shared sleeping spaces during peak season. Evening and morning meals are provided as part of the nightly rate, featuring simple mountain cooking using provisions carried in or stored at the hut. Hot shower facilities are not available; basic washing facilities only. Composting toilets serve the facility, consistent with the national park's environmental management principles.
The surrounding Ozenuma area is a primary destination for birdwatching, wetland photography, and quiet trekking along well-maintained boardwalk paths. The Ozenuma Pond reflects the surrounding mountain ridges in calm conditions. Reservations are required well in advance, particularly for the June and early July peak season when the skunk cabbage fields are at their most spectacular.
Room types
- Dormitory-style tatami rooms
- Small private rooms (limited)
Amenities
- Basic tatami sleeping areas
- Shared meals
- Composting toilets
- No hot water shower
- Stunning wetland location
- Reservations essential
Location
Ozenuma area, Katashina-mura, Tone-gun, Gunma 378-0414
36.9156, 139.1698 View on map
Highlights
- Unique Ramsar wetland location at 1,400 m in Oze National Park, Gunma
- Accessible only on foot via 2–4 hour trail approaches—no road access
- Summer skunk cabbage blooms and cotton grass fields around Ozenuma Pond
- Full board (dinner and breakfast) included in the nightly mountain hut rate
- Spectacular wetland boardwalk walks and birdwatching from the hut doorstep
Tips for visiting
- Reserve well in advance—especially for June and early July when the Lysichiton camtschatcensis (Asian skunk cabbage) blooms. This is the busiest period and huts fill months ahead.
- Pack rain gear regardless of the forecast; the Oze wetland creates its own microclimate with frequent afternoon cloud and rain.
- Carry sufficient yen cash as the mountain hut cannot process card payments.
- Trekking poles are recommended for the descent from the wetland plateau; some trail sections involve steep stair-cut paths on the approach from Hatomachi-toge.
- The hut operates only late May to late October; plan the visit within the seasonal window and verify the opening date in the year of visit.
Accessibility
Oze no Koya Mountain Hut is accessible only by foot via mountain trails of 2–4 hours duration. Wheelchair access and adapted facilities are not available, and the terrain is unsuitable for visitors with mobility limitations. The hut's location within a protected national park limits infrastructure development.
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Frequently asked questions
How do visitors reach Oze no Koya Mountain Hut?
The hut is accessible only on foot. The most common approaches are from Hatomachi-toge trailhead (2.5–3 hours), Oshimizu trailhead (approximately 3 hours), or Fujimi-Shita trailhead (approximately 4 hours). Trailheads are reached by bus from Numata City or from the Jōetsu Shinkansen station at Jōmō-Kogen.
What is the best season to visit Oze National Park and the mountain hut?
Late May to mid-June is peak season for the Asian skunk cabbage blooms that make Ozenuma internationally known. August sees the cotton grass in full display. Autumn foliage (late September to mid-October) is the second most popular period. The hut closes after late October when snow makes trails hazardous.
What should guests bring to a mountain hut stay?
Essential items include rain gear, layered clothing (temperatures at 1,400 m are significantly cooler than the valley), waterproof boots or trail shoes, a headlamp or torch, sufficient cash, any personal medications, and toiletries. Bedding is provided; sleeping bags are not required but a liner can be useful.
Are hot spring baths or showers available at the hut?
No. The mountain hut does not have hot spring baths or hot showers. Basic washing facilities (cold water) are available. Guests seeking onsen bathing should plan a post-trek stay at one of the Minakami or Katashina valley hot spring inns.