Mount Daibosatsurei Day-Hike Report: Loop from Kamihikawa Pass via Karamatsu Ridge, Kaminari-iwa, and Daibosatsu Pass

Introduction

On May 5, 2026 (Children's Day), I climbed Mount Daibosatsurei (大菩薩嶺, 2,057 m) in Koshu City, Yamanashi Prefecture—one of the 100 Famous Japanese Mountains (Nihon Hyakumeizan).

Starting from Kamihikawa Pass (上日川峠), I walked past Fukuchan-so Lodge (福ちゃん荘), climbed the Karamatsu Ridge (唐松尾根) to Kaminari-iwa (雷岩) and the wooded summit of Mount Daibosatsurei, and then followed the open sky-ridge south past Sainokawara (賽ノ河原) and Oyashirazu-no-Atama (親不知ノ頭) to Daibosatsu Pass (大菩薩峠) before descending past Shoen-so and Fukuchan-so back to Kamihikawa Pass.

I chose Mount Daibosatsurei because it is accessible from the Tokyo area and renowned for its approachable 2,000 m ridgeline—making it my very first Hyakumeizan climb. Below is my complete GPS log from Yamareco along with official parking, bus, and mountain hut information.

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Hike Summary (May 5, 2026)

Note: Because my recorded pace (0.7–0.8× standard time) was faster than average, plan for 4 to 5 hours when walking at standard map pace.

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About Mount Daibosatsurei

• Elevation: 2,057 m in Koshu City, Yamanashi Prefecture (part of Chichibu-Tama-Kai National Park and one of the 100 Famous Japanese Mountains).
• Character: While the true 2,057 m summit sits inside subalpine forest with no view, the open ridgeline between Kaminari-iwa (approx. 2,036 m) and Daibosatsu Pass (approx. 1,897 m) commands sweeping panoramas of Mount Fuji, Lake Daibosatsu, the Southern Alps, and the Kofu Basin.
• High trailhead access: Because cars and seasonal buses reach Kamihikawa Pass (approx. 1,590 m), hikers can step onto a 2,000 m alpine ridge on a comfortable day trip.

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GPS Route Map & Split Times

• Total elapsed time: 3 hr 46 min (3 hr 29 min moving, 12 min rest per Yamareco log)
• Ascent (Kamihikawa Pass → Summit): approx. 1 hr 30 min
• Ridgeline traverse (Kaminari-iwa → Daibosatsu Pass): approx. 36 min
• Descent (Daibosatsu Pass → Kamihikawa Pass): approx. 45 min

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Section-by-Section Trail Log

1. Start to Kamihikawa Pass (11:26 – 11:47)

I drove to the mountain for this hike. Knowing how crowded Mount Daibosatsurei gets during Golden Week, I aimed to arrive around 11:00 AM hoping to catch spaces vacated by early-morning hikers. Even at that hour, the upper parking lots were packed, so I parked near the north shore of Lake Daibosatsu (大菩薩湖), about 1.5 km southeast of Kamihikawa Pass, and walked 19 minutes up to Kamihikawa Pass (approx. 1,590 m).

2. Kamihikawa Pass to Fukuchan-so (11:47 – 12:13)

Leaving Kamihikawa Pass at 11:47, I reached Fukuchan-so Lodge (福ちゃん荘) in 20 minutes (12:07), gaining about 110 m of elevation. After a 6-minute restroom break, I set off at 12:13.

Fukuchan-so sits right where the Karamatsu Ridge trail branches off from the wider track toward Daibosatsu Pass. Because mobile reception is unstable here, the lodge accepts cash only.

3. Climbing Karamatsu Ridge to Kaminari-iwa (12:13 – 13:07)

From Fukuchan-so, I took the steeper Karamatsu Ridge (唐松尾根) trail uphill. It took 54 minutes and gained roughly 330 m of elevation to reach Kaminari-iwa (雷岩, approx. 2,036 m)—the steepest sustained climb of the loop. Partway up the ridge, views of Mount Fuji and Lake Daibosatsu opened through the trees.

I reached Kaminari-iwa at 13:07 under a nearly cloudless sky. Directly ahead stood Mount Fuji with Lake Daibosatsu (Kamihikawa Dam reservoir) gleaming in the foreground—an unforgettable view with dozens of hikers relaxing across the rocks.

4. Mount Daibosatsurei Summit & Deer Encounter (13:17 – 13:21)

From Kaminari-iwa, a 10-minute walk through the conifers brought me to the summit of Mount Daibosatsurei (2,057 m) at 13:17. Surrounded by dense forest, the summit post has almost no outward view, so I stayed 4 minutes before heading back to Kaminari-iwa.

What made the wooded summit special that day was a lucky encounter with wild sika deer (鹿) crossing the trail right in front of us and standing quietly among the hemlock trees.

5. Ridgeline Walk from Kaminari-iwa to Daibosatsu Pass (13:33 – 14:09)

Returning to Kaminari-iwa at 13:33, I began the highlight of the hike: the open ridgeline walk south to Daibosatsu Pass, passing Kanbe-iwa (13:41), Sainokawara (賽ノ河原, 13:55), and Oyashirazu-no-Atama (親不知ノ頭, 14:00) to reach Daibosatsu Pass (大菩薩峠, approx. 1,897 m) at 14:09 (about 36 minutes and -140 m elevation change).

With nothing to block the wind on either side of the ridge, the breeze felt bitingly cold despite the bright sunshine, so I pulled a windbreaker on over my long-sleeved shirt.

6. Descent from Daibosatsu Pass to Kamihikawa Pass (14:09 – 15:12)

From Daibosatsu Pass (where Kaizan-so Lodge stands), I descended along the wide track past Shoen-so (14:31) and Fukuchan-so (14:44), arriving back at Kamihikawa Pass at 14:54 (45 minutes, -310 m) and reaching my car at 15:12.

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Weather on May 5, 2026

According to the Japan Meteorological Agency's nearby Katsunuma AMeDAS station (Koshu City, elevation 394 m), May 5, 2026 was completely dry with unbroken sunshine between 11:00 and 15:00, valley temperatures of 19–24°C, and low relative humidity of 15–23% (following 11.0 mm of rain on May 4 that washed the air crystal clear). Because the 2,000 m ridgeline sits more than 1,500 m higher than Katsunuma, ridge temperatures were roughly 10°C cooler—and felt colder still in the exposed wind.

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Official Access, Parking & Bus Information

By Car

According to Koshu City's official tourism portal, Kamihikawa Pass (上日川峠) is about 40 minutes by car from Katsunuma IC on the Chuo Expressway via Prefectural Route 201 or 218.

Because Lots 1–3 fill very early on weekends, Golden Week, and autumn foliage days, Koshu City encourages drivers arriving from the Yamato-cho side to use Parking Lot No. 4 (300 spaces).

By Train & Seasonal Bus

From JR Kai-Yamato Station (甲斐大和駅) on the JR Chuo Main Line, Eiwa Kotsu (栄和交通) operates the seasonal Daibosatsu Kamihikawa Pass Line (running weekends, holidays, and select weekdays from April 18 to December 13, 2026; one-way fare 1,020 yen adult / 510 yen child).

Groups of 15 or more passengers must contact Eiwa Kotsu in advance. Alternatively, a taxi from JR Enzan Station takes approx. 30 minutes (around 5,500 yen per Koshu City).

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Mountain Huts Along the Route

• Fukuchan-so (福ちゃん荘): Located at the junction of Karamatsu Ridge and the Daibosatsu Pass track. Cash only due to weak cell reception; the lodge asks visitors not to photograph staff or post images of staff on social media without permission.
• Kaizan-so (介山荘): Located at Daibosatsu Pass (1,897 m). According to Koshu City's tourism guide, lodging is 8,500 yen (1 night with 2 meals) or 6,000 yen (without meals), open year-round with irregular weekday closures.

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Takeaways for Future Hikers

1. Watch the 15:45 final bus if you start late: At a standard map pace, starting at 11:30 AM would put your finish after 16:00—past the final 15:45 bus from Kamihikawa Pass. Bus riders should take the 08:10 or 09:20 morning bus.
2. Spend your rest time on Kaminari-iwa and the ridge: Since the 2,057 m summit is enclosed in forest, plan your lunch and photo breaks on Kaminari-iwa or along the open ridge toward Daibosatsu Pass.
3. Carry cash and a windproof layer: Even on a sunny May afternoon, the exposed 2,000 m ridgeline wind is cold, and mountain huts along the route require cash for restrooms and refreshments.

Reference Links

• Koshu City Official Tourism Portal: Mount Daibosatsurei
• Koshu City Official Tourism Portal: Daibosatsu Trekking Courses
• Koshu City Official Tourism Portal: Mount Daibosatsu Parking Guide (Lots 1–4)
• Eiwa Kotsu: Local Bus Timetables & Fares (Kai-Yamato Station – Kamihikawa Pass)
• Koshu City Official Tourism Portal: Kaizan-so Lodge
• Koshu City Official Tourism Portal: Fukuchan-so Lodge
• Japan Meteorological Agency: Historical Weather Data — Katsunuma Hourly Values (May 5, 2026)
• Japan Meteorological Agency: Historical Weather Data — Katsunuma Daily Values (May 2026)