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Oonoyama (723 m) | A Beginner's Winter Hike from Yaga Station, with Mt. Fuji and How I Stay Warm

2026.01.10

Walk from the station, and get a full-frontal view of Mt. Fuji from the top. Oonoyama (723 m) in Yamakita, Kanagawa Prefecture, delivers both of those without asking much of you. I went as the first hike of the year, to shake off a New Year holiday spent sitting down.

This post covers the standard route — up from Yaga Station and down to Yamakita Station — plus the snow-covered Fuji with a lenticular cloud above it, a trail that's kind to beginners and has toilets along it, and the winter layering I actually use, along with a few facts about cold-weather hiking that are worth knowing. If you'd like to start winter hiking with something gentle, this is a good place to look.

The route at a glance

• Area: West Tanzawa — Oonoyama, in Yamakita, Ashigarakami District, Kanagawa Prefecture
• Height: 723.1 m (per the summit marker)
• Our route: Yaga Station → Oonoyama trailhead → summit → Jizo-iwa route → Yamakita Station
• Distance and ascent: about 10 km, roughly 700 m of climbing
• Walking time: about 5 hours (there's little that's hazardous, so in practice you can take it more slowly than that)
• Access: start at Yaga Station on the JR Gotemba Line, finish at Yamakita Station on the same line. By car, there's a car park near the top (room for about 20) from which the summit is under five minutes on foot — which makes it workable with small children
• Difficulty: ★☆☆☆☆ (beginner). The trail is well maintained, and there are several toilets along the way

A low mountain that works even if you aren't confident in your fitness, with a first-rate view. Exactly right for the first hike of a year.

Starting at Yaga Station — reassuringly well supplied with toilets

The start is Yaga, a small station on the JR Gotemba Line. Mt. Fuji was already clearly visible from the platform, the weather was good, and expectations rose accordingly. It was 8 a.m. and cold, but the white Fuji I'd been watching from the train window had put me in a good mood before we'd taken a step.

From the station to the trailhead is about 30 minutes on paved road, with Mt. Fuji in view the whole way, so it never drags. What's genuinely useful is that there are toilets at the key points: at the station, before the trailhead, and at the summit. If facilities in the mountains are a worry for you, this route removes it. I'd read about it beforehand, but walking it, I realised how much that matters to someone starting out.

Snow on Fuji, and a lenticular cloud above it

The main reward on Oonoyama is the view of Mt. Fuji. It's on your left from the road to the trailhead and stays there once you're on the trail. That day it was white to well down its flanks, and I kept stopping to look at it.

Above it sat a tsurushi-gumo, a lenticular cloud — a rugby-ball-shaped lens of cloud that forms fairly often around Mt. Fuji and is quite a thing to see. It's beautiful, though it's also said to be a sign that the weather is about to turn. We were lucky and the fine weather held all day, so we got the whole extravagant combination: blue sky, a snow-covered Fuji, and that strange shape floating over it.

A pastoral walk — an honesty-box stall and carved animals

The trail on Oonoyama is easy to follow — there's very little scope for going wrong — and pleasant underfoot. It was pasture once, so as you get closer to the summit the view opens and the mood turns bright and rural. There are cow sculptures and carved wooden animals scattered about (a rooster among them), the kind of small, playful touches that make you smile as you walk.

There's also an unstaffed stall along the way selling things local people have made: yuzu, umeboshi, oni-yuzu jam, all of it tempting. And an old weeping cherry, around 11 m tall, designated a natural monument by the town of Yamakita. Getting a look at the life and history of the countryside as well as climbing something — that's part of what makes Oonoyama enjoyable.

The summit (723.1 m) — open grassland and the Tanzawa range

Partway up we stopped for an early lunch at a covered rest area. It's a spot I'd recommend: the view of Mt. Fuji is excellent, and the building behind it blocks the north wind, so it's calmer than the summit. Lunch was a small cup noodle and onigiri. A small cup noodle means you can finish the soup even on a cold day, which warms you from the inside.

Then up to the top. The summit of Oonoyama, at 723.1 m, is a broad open clearing, with a full 360 degrees of view around the marker. Mt. Fuji, of course, but also Oomuroyama, Hinokiboramaru, Hirugatake and the rest of the Tanzawa range — naming them off one by one is a good way to spend a while. The more you climb, the more the mountains start to arrange themselves in your head, and that feeling is one of the real pleasures of hiking. There's covered seating and a clean toilet at the top too, so it's an easy place to linger.

The winter gear that worked for me

The cold-weather part of the title. Here's what I actually tried, and what earned its place.

• Adjust your layers constantly: it can be freezing at the start and you'll be sweating within minutes of starting to climb. If you're hot, take something off rather than putting up with it; if you're about to stop and cool down, put something on. That unglamorous, repeated adjustment is the single biggest factor in a comfortable winter day on a low mountain.
• Thin rubber gloves under your gloves: I put ordinary household rubber gloves — the washing-up sort — under my hiking gloves. They stop wind and water, which suited the morning cold, and they don't get in the way of using a phone. Bare hands go cold the instant you take your gloves off; with these underneath, much less so. They do get sweaty, though, so treat them as something to remove once the temperature comes up.
• A thermos of hot water: it lets you make hot noodles or soup without lighting a stove, so there's less to carry and less to do. Ideal winter trail food.
• A sit mat, to stop the cold coming up: I sit on a Montbell tatami pad at breaks and simply don't feel the cold from the ground. It folds down small and is versatile enough to double as a bench seat at sports events — a reliable winter companion.

One note: my left knee started hurting on the way down. To keep hiking for a long time I'm looking at a knee support (Zamst and similar). If your knees are a concern, pace yourself and place your feet carefully on descents.

A few things worth knowing about winter hiking

Some small things I got curious about at the summit and looked up afterwards.

• Dehydration hides in winter: you don't feel thirsty in the cold, so it's easy to forget to drink. But even when you don't think you're sweating, you lose a steady amount of water simply by breathing. A headache while you're walking may well be the first sign. Drinking little and often matters more in winter, not less.
• Needing the toilet more often is normal: in the cold, blood vessels constrict and the body decides it doesn't need to hold on to as much water. Which is another reason a mountain as well supplied with toilets as Oonoyama is easy going in winter.
• Quiet mountains carry sound: when the air is clear, footsteps and wind and the movement of the trees all come through with unusual clarity. I turned around to check behind me more than once. It's a strange sensation, and particular to a quiet winter mountain.

Also: despite all that climbing and descending, I somehow weigh more when I get home. That one I could not find an answer to, no matter how much I read. If you know why, do tell me.

Down to Yamakita Station — the Jizo-iwa route, a bath and ramen

For the descent I took the Jizo-iwa route, a trail route with no traffic on it, down to Yamakita Station. Honestly, the way down toward Yamakita is a bit rougher than the climb from Yaga. In terms of easy walking, the Yaga side is the better maintained of the two, so if you're planning this, going up from Yaga and down to Yamakita — the direction we took — is the more comfortable way round.

The reward afterwards is a bath. There's a day-use hot spring right by Yamakita Station, and after washing off the day we finished with a strongly flavoured miso ramen. A soak and a bowl after a walk is the best thing about winter hiking on low mountains.

In short: a good first hike of the year

Oonoyama has everything I'd want to recommend to a beginner in winter: you can reach it on foot from a station, the view of a snow-covered Mt. Fuji is first-rate, the walking is easy, and there are toilets. Having done it, my honest reaction is that someone who has only just started hiking would find this very manageable.

The one thing I'd do differently is my knees, which complained on the descent — next time I'll prepare for that properly. Winter hiking is largely a matter of small preparations stacking up, layering and drinking among them, and they make a large difference to both comfort and safety. If this nudges you toward your first winter walk, I'm glad. Dress warmly, leave yourself time, and go and see Mt. Fuji from Oonoyama.

🛒 See the gear from the video as a list → A packing list for your first low-mountain hike

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