Mt. Kobushi — Following the Chikuma River to Its Source at a Three-Province Peak

Trail Overview

Mt. Kobushi (甲武信ヶ岳, Kobushi-ga-take, 2,475m) stands at the three-prefecture junction of Yamanashi (甲州), Saitama (武州), and Nagano (信州) — its name derives from the first characters of these three provinces. It is one of the main peaks of the Oku-Chichibu mountain range and a Hyakumeizan.

The mountain is notable as the source of the Chikuma River (Shinano River) — Japan’s longest river. The popular route from Moki-daira follows the river upstream to its very origin, combining river exploration with mountain climbing.

Recommended Route: Moki-daira to Mt. Kobushi via Chikuma River Source (Round Trip)

Starting from Moki-daira in Kawakami Village, Nagano Prefecture, this route follows the Chikuma River to its source before climbing to the summit.

Course Time

Section	Duration
Moki-daira Parking → Chikuma River Trail Entrance	About 10 min
Trail Entrance → Name-taki (Waterfall)	About 1.5 hours
Name-taki → Chikuma River Source Marker	About 1.5 hours
Source Marker → Oku-Chichibu Ridge Trail Junction	About 30 min
Junction → Mt. Kobushi Summit	About 30 min
Mt. Kobushi Summit → Moki-daira Parking (descent)	About 3.5 hours
Total (round trip)	About 8-9 hours

Tip: As the stream gradually narrows approaching the source marker, watching the birth of Japan’s longest river from a rock seep is a deeply moving experience.

Mountain Hut Option: If a day hike feels too ambitious, Kobushi-goya (about 15 min below the summit) offers accommodation from late April to late November. Capacity about 50 — reservations required.

Access Information

• Nearest Station: JR Koumi Line, Shinano-Kawakami Station
• From Tokyo: JR Chuo Main Line to Kobuchizawa (about 2 hours) → JR Koumi Line to Shinano-Kawakami (about 50 min)
• To Trailhead: Taxi from Shinano-Kawakami Station to Moki-daira, about 30 min. No public transport beyond the station — taxi or car required
• By Car: Chuo Expressway Sutama IC → Route 141 and Prefectural Route 68, about 1.5 hours. Free parking at Moki-daira (about 30 spaces)
• Note: The forest road to Moki-daira is closed in winter (typically December through April)

Convenience Stores, Shops & Restrooms

Convenience Stores (within 5 min of trailhead)

• 7-Eleven Kawakami Village: Along Route 141 — last convenience store on the way to Moki-daira
• No shops near Moki-daira. Stock up in Kawakami Village

Shops & Teahouses

• Kobushi-goya: Mountain hut near the summit with beverages and light meals (during operating season only)
• No shops at the Moki-daira trailhead

Restrooms

• Moki-daira Parking: Public restrooms available
• Kobushi-goya: Restrooms available (may be available to non-guests)
• No restrooms along the trail — use facilities before departure

Highlights

Chikuma River Source

• The birthplace of Japan’s longest river (367km as the Shinano River)
• Clear water seeping from moss-covered rocks — a mystical and moving sight

Name-taki Waterfall

• A beautiful cascade where water flows over a single smooth rock face
• Especially scenic during fresh spring greenery and autumn foliage

Rhododendron Colonies (June)

• Azuma-shakunage rhododendrons bloom along the ridgeline near the summit
• Pink flowers adorn the trail in early to mid-June

Summit Panorama

• From the summit, enjoy views of Mt. Fuji, Mt. Yatsugatake, the Southern Alps, and the Northern Alps
• On clear days, a 360-degree panorama unfolds

Oku-Chichibu Primeval Forest

• Dense Maries’ fir and northern Japanese hemlock forests draped in moss
• Experience the deep, atmospheric forests characteristic of Oku-Chichibu

Gear Checklist

• ✅ Hiking boots (muddy sections and tree roots — high-cut recommended)
• ✅ Rain jacket and pants
• ✅ Lunch and trail snacks (no shops — bring plenty)
• ✅ Water (minimum 2L — stream water should be filtered or boiled)
• ✅ Warm layer (2,475m — ridgeline winds can be cold)
• ✅ Headlamp (long course time — essential backup)
• ✅ Map and GPS
• ⬜ Trekking poles (reduce fatigue on the long distance)
• ⬜ Gaiters (for muddy trail sections)

Important Notes

• Long course time: 8-9 hours requires a pre-dawn start (by 5:00-5:30 AM)
• Winter road closure: The forest road to Moki-daira closes December through April
• Water sources: The Chikuma River provides water along the route, but filter or boil before drinking
• Cell phone reception: Signal is unreliable in the deep valley sections