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Kumotoriyama via the Kamosawa Route | A Day-Hike Guide to Tokyo's Highest Peak, in Autumn Colour

2024.11.30

"There's a mountain over 2,000 m inside Tokyo." That surprises a lot of people. The mountain in question is Kumotoriyama (2,017 m), the highest point in the Tokyo metropolis and one of Japan's 100 Famous Mountains. I climbed it as a day hike from the Kamosawa route, the most-walked way up, right as the autumn colour was coming in. The panorama from the open Ishione ridge did not feel like something only a few hours from central Tokyo.

The conclusion first: the Kamosawa route has almost nothing technical about it — no chains, no real rock — but it is long, and it asks a lot of your legs. As a day hike it suits strong walkers; with a night in a mountain hut, it's well within reach of someone who has only recently started hiking. Below is how the route flows, what's worth seeing, the difficulty, access, and what it takes to finish a one-day round trip safely, from my own day on the hill.

Route overview (Kamosawa route, day hike)

• Area: The Okutama and Okuchichibu region, where Tokyo, Saitama and Yamanashi meet
• Peak and elevation: Kumotoriyama, 2,017 m — the highest point in Tokyo and a Hyakumeizan summit
• This route: Kamosawa → Kosode-nokkoshi → Dodokoro → Nanatsuishiyama (1,757 m) → Bunazaka → Ishione ridge → Ko-Kumotoriyama → Kumotoriyama, and back the same way
• Distance: Over 20 km round trip (about 11 km each way from Kamosawa)
• Elevation gain: Roughly 1,500 m from the trailhead
• Book time: Around 9 to 10 hours for the round trip — a long day
• Difficulty: ★★★☆☆. Little that's technical, but the distance and the repeated re-ascents demand real staying power

Kumotoriyama is 2,017 m, but the trailhead sits at only 500 to 600 m, which is why the accumulated gain is so large. There are no steep chained sections; instead there's a very long climb and a series of re-ascents that quietly wear you down. If you're doing it in a day, an early start is non-negotiable.

What Kumotoriyama is

Kumotoriyama stands on the ridge where Tokyo, Saitama and Yamanashi meet, and it's fair to call it the dominant peak of the Okutama range. At 2,017 m it is the highest ground in Tokyo, and Kyuya Fukada included it in his 100 Famous Japanese Mountains.

Because its elevation matches the year, crowds of hikers made a point of climbing it in 2017. What draws people, I think — and I felt this strongly walking it — is the gap between how easily you can get here from the city and how genuinely alpine the upper mountain feels. You start in forest at the bottom, the sky comes closer as you climb, and at the end the view opens completely. One mountain changing character that much is a large part of the appeal.

Access: starting from Kamosawa or Kosode-nokkoshi

The Kamosawa route starts on the Yamanashi side, in Tabayama Village. By public transport, take a bus from Okutama Station on the JR Ome Line and get off at the Kamosawa stop. By car, the parking area at Kosode-nokkoshi, a little above Kamosawa, cuts out some of the road walking at the start. This is a popular mountain and the parking fills early, so give yourself time.

The trail begins past a few houses, and from there it's 1,500 m of height to the summit.

Kamosawa to Nanatsuishiyama — the long climb through forest

For a good while the trail gains height gently through forest. The gradient is never harsh; what defines the Kamosawa route is simply how long it is. Holding a steady pace without rushing is what leaves you something in reserve later.

Past Dodokoro, the climbing gradually gets more serious. The trail then splits: one branch goes over the summit of Nanatsuishiyama (1,757 m), the other contours around it. If you have the fitness and the time, I'd take the summit. Just below it is the Nanatsuishi hut with a water source — a reassuring resupply point even on a day trip.

From the top of Nanatsuishiyama you can see the whole ridge running on toward Kumotoriyama. "That far, then," I thought — and at the same time you can tell from up there that the scenery ahead is going to be worth it.

Bunazaka to the Ishione ridge — autumn colour on the crest

Drop down off Nanatsuishiyama and you reach the junction at Bunazaka, the entrance to the Ishione ridge that leads to Kumotoriyama. The forest ends and a broad open ridge — cut wide as a firebreak — runs along the crest as far as you can see.

The Ishione is the highlight of the whole route. The view opens on both sides, and in good weather Mount Fuji and the Okuchichibu peaks come out. I walked it in autumn, and the contrast between the turning trees, the grass moving on the ridge and the clear sky was genuinely beautiful. Partway along there's a single tree standing alone on the crest, and most hikers stop there to take a photo.

The Ishione is wonderfully open, and it's also a stretch of repeated gentle re-ascents. With the scenery to carry you along, you go over Ko-Kumotoriyama and head for the last climb toward the emergency hut below the summit.

2,017 m — the summit

Past Ko-Kumotoriyama, once the emergency hut comes into view, the top is close. Finish the last climb, step out into the open, and you're on the summit of Kumotoriyama, the highest point in Tokyo. Because you've walked so far to get there, the sense of completion is considerable.

The summit is broad and open, and in good conditions you can see Mount Fuji, the Southern Alps and the Okuchichibu peaks. It's an unmistakably high-mountain view, which is hard to reconcile with being a few hours from central Tokyo. This is the moment the long approach makes sense.

Just north of the summit, on the Saitama side, is Kumotori Sanso, a hut where you can stay the night. Splitting the trip over two days gives you far more slack in your schedule, plus the quiet of a mountain morning and evening and the clean air at dawn. For anyone newer to hiking, I'd genuinely recommend the hut version over the day trip, simply because the plan has room in it.

Doing it in a day: fitness, timing and kit

The things I paid most attention to on this round trip.

• Start early: with a book time this long, you need to be off the mountain in daylight. From autumn onward, when it gets dark early, managing your hours is directly a safety matter.
• Pacing is everything: with little technical ground, endurance decides the day. Don't burn energy on the forest section at the start; a steady pace pays off on the re-ascents later.
• Carry extra water and food: water sources are limited, essentially to the Nanatsuishi hut. Bring more than you think you need so you can keep topping up.
• Layers and weather: a ridge at 2,000 m feels nothing like the valley. Bring a windproof layer, hat and gloves in any season. The Ishione is exposed, so bear in mind there's little shelter if wind or rain arrives.
• Bears: Okutama is Asiatic black bear country. Use a bell and make your presence known as a matter of course.
• Map and plan: know where the junctions are — particularly the Nanatsuishiyama summit versus the bypass trail — and check your position with a map app as you go.

Handle those and Kumotoriyama is not an unreasonable mountain. Just don't lose sight of the fact that the day version is a long haul that comes down to fitness. Choosing honestly between the day trip and the hut, based on where you actually are, is the single best way to enjoy this mountain safely.

What I came away with

Kumotoriyama earns both its titles — highest point in Tokyo, and Hyakumeizan peak. It gives you forest and open ridge in a single day, with very little that's frightening and plenty that's demanding, in distance and in height gained. And the moment you step out onto the Ishione, with the ridge in autumn colour, the tiredness of the long climb simply drops away.

If you're planning it, start by being honest about your fitness. Strong walkers can do the day trip with an early start; if you'd rather take the mountain slowly, book a night at Kumotori Sanso. Either way, I suspect you'll be surprised that a mountain like this is reachable from central Tokyo at all. Plan within your limits, take the right kit, and go and walk the highest ridge in Tokyo.

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