Mt. Sukaisan (すかいさん, 2,144m) straddles the border of Nikko City (Ashio Town), Tochigi and Numata City, Gunma in Nikko National Park, selected in Kyuya Fukada’s One Hundred Mountains of Japan. Known as a “finishing peak for Hyakumeizan completionists”, it is one of the most remote major peaks in the Kanto region.
The former shortest route — the Kuriharagawa forest-road Sukaibashi course (Gunma side, 4.5-hour round trip) — was permanently closed after the October 2019 Typhoon Hagibis caused massive collapse of the forest road, declared in March 2020 as “no recovery planned”. The only realistic route now is the classic route from Ginzandaira → Mt. Koshin → Mt. Nokogiri → Mt. Sukaisan (Tochigi side): Expert ★★★★★・distance ~22 km・action time 14 hr 20 min・1 night 2 days at Koshin Hut is standard.
Access to the trailhead
- [Outbound / Return] Tsudo Station ⇔ Ginzandaira (on foot / taxi)
- Classic route, Koshin Hut, suggested plans
Course time (Classic route, 1 night 2 days, Expert, ~14 hr 20 min)
Day 1 (~4 hr): Ginzandaira parking (820 m) → (1:00) → Ichi-no-Torii → (2:00) → Koshin Hut (1,500 m) overnight
Day 2 (~10 hr): Koshin Hut → (1:30) → Mt. Koshin (1,892 m) → (2:30) → Mt. Nokogiri (1,998 m, chain sections) → (1:30) → Mt. Sukaisan summit (2,144 m) → descent (4:30) → Ginzandaira
1. [Outbound / Return] Tsudo Station ⇔ Ginzandaira (on foot / taxi)
From Tsudo Station to Ginzandaira trailhead (820 m, 50-car parking, free), no scheduled bus service; walking ~1 hr 40 min・taxi ~¥3,000. By private car: Kita-Kanto Expressway Isesaki IC → R17 → Pref. Rd 73 → R122 → Ashio Tunnel → Pref. Rd 293 Koshinzan Park Line → left-side parking after Kokumin-shukusha Kajikaso, ~2 hr 30 min. Ginzandaira parking 50 spaces + 5 at gate, free. After descent, Kokumin-shukusha “Kajikaso” (day-use bath ¥800, 11:00-15:00 last reception 14:30) is recommended.
Operating period : No scheduled bus; walking / taxi / private car year-round (closed in winter snow season)
Travel time : Tsudo Stn → Ginzandaira walking ~1 hr 40 min・taxi ~20 min
Fare : Taxi ~¥3,000 (one-way)
Frequency : No public transport — reservation taxi required
Tsudo Stn → Ginzandaira (walking / taxi, no scheduled bus, reference)
| Tsudo Stn dep | Ginzandaira arr |
|---|---|
| Walking (any time) | ~1 hr 40 min |
| Taxi (reservation required) | ~20 min・¥3,000 |
Note : No scheduled bus. Reservation is required for taxis (return taxi arrangement is difficult at Ginzandaira, so reserving both legs is recommended). Private car is overwhelmingly standard. Kajikaso lodging or pre-overnight + post-descent bath + reserved return taxi as a set is realistic.
Reference : Tozanguchi Navi — Ginzandaira parking ｜ Mt. Sukaisan Classic Route Details
Contact : Kokumin-shukusha Kajikaso ☎0288-93-3420 / Nikko City Ashio Tourism ☎0288-93-3116 / Numata Taxi ☎0278-22-2055
2. Classic route, Koshin Hut, suggested plans
About Mt. Sukaisan
At 2,144 m, straddling Nikko City (Tochigi) and Numata City (Gunma), within Nikko National Park. Selected in Kyuya Fukada’s One Hundred Mountains of Japan, one of Kanto’s most remote major peaks. Known as the “finishing peak for Hyakumeizan completionists”. The summit is tree-enclosed with limited views, but the classic route’s Koshin → Nokogiri → Sukaisan rocky ridge traverse is one of Kanto’s most rewarding ridge expeditions.
Trail overview (currently the only realistic route)
- Classic route (Tochigi side) (Expert, ~14 hr 20 min, 1 night 2 days) : Ginzandaira → Ichi-no-Torii → Koshin Hut → Mt. Koshin → Mt. Nokogiri (chain sections) → Mt. Sukaisan round trip, or Rokurinhan-toge circuit
- (Reference) Sukaibashi course (Gunma side): Permanently impassable since 2019 Kuriharagawa forest road collapse; Sukaibashi trailhead inaccessible
Mountain huts / hot springs (2026 information)
– Koshin Hut (1,500 m, unstaffed emergency shelter, no phone): Scheduled to reopen April 2026 (renovation completed). Self-catering, bring own bedding. Verify availability with Nikko City Ashio Tourism ☎0288-93-3116
– Kokumin-shukusha “Kajikaso” (Ginzandaira, ☎0288-93-3420): Lodging ¥9,000~・day-use bath ¥800 (11:00-15:00); ideal climbing base
– Ginzandaira parking: 50 spaces + 5 at gate, free
Climbing season / flora: Early June to late October. June: Koshinso (Pinguicula ramosa, an endemic carnivorous plant of Mt. Koshin, endangered), rhododendron, virgin forest. October: autumn colors. Snow and ice remain on the ridge / chain sections until early June.
Cautions
– Kuriharagawa forest road permanently impassable: Gunma-side Sukaibashi course is effectively defunct
– Nokogiri ridge is Expert chain-only: Falls are immediately serious; not for beginners
– Verify Koshin Hut availability in advance: April 2026 reopening planned; check with Nikko City office
– Limited water sources: Koshin Hut, Fudosawa; carry at least 2 L
– No scheduled bus: Taxi or private car; only Docomo mobile reception
Emergency contacts / inquiries
- Nikko City Ashio Tourism: ☎0288-93-3116 / Numata City Tourism: ☎0278-23-2111
- Nikko Police Station (climbing notification / mountain rescue): ☎0288-53-0110
- Kokumin-shukusha Kajikaso (Ginzandaira): ☎0288-93-3420
- Numata Taxi: ☎0278-22-2055 / Watarase Keikoku Railway: ☎0277-73-2110
Suggested plans (Classic route, 1 night 2 days at Koshin Hut, recommended, standard)
- 1 night 2 days at Koshin Hut (recommended, standard): Day 1 Tokyo 9:00 → Tsudo Stn 13:00 → taxi → Ginzandaira 13:30 → Ichi-no-Torii 14:30 → Koshin Hut 16:30 overnight. Day 2 Koshin Hut 4:00 → Mt. Koshin 5:30 → Mt. Nokogiri 8:00 → Mt. Sukaisan 9:30 → descent → Ginzandaira 16:00 → Kajikaso bath → return
- 2 nights 3 days, Kajikaso pre-overnight + Koshin Hut + circuit (for strong hikers): Day 1 Kajikaso pre-overnight. Day 2 Koshin Hut overnight. Day 3 summit → descent via Rokurinhan-toge → Kajikaso → return
Reference : Numata City — Kuriharagawa forest road impassable official ｜ Mt. Sukaisan classic route details
Photo by Koda6029
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