[Northern Alps] Mt. Jonen East Ridge | A 23km endurance battle in deep winter, and the view of Mt. Yari beyond

Introduction

From the East Ridge in deep winter to Mt. Jonen.
This is a long route of over 23km and 2,300m of cumulative elevation gain that can only be walked in winter.

The memory of walking the Mt. Jiigatake East Ridge two years ago has stayed with me, and I decided that 'this is next'.

The Mt. Jonen East Ridge does not have any flashy knife ridges.
However, it is long. It is just plain long.

Rather than technical, it is a route of endurance that quietly wears you down.

The view of Mt. Yari that appeared beyond was
a sight permitted only on days when all conditions align.

In this article, I will summarize based on my actual experience:

• Actual conditions of the winter East Ridge

• Timing for equipment decisions

• Crux points from Mae-Jonen to the summit

I will summarize these based on my actual experience.

By the way, I have also walked the Mt. Jiigatake East Ridge, which is another winter-only route.
It is a route specialized for steep climbs, and its character is quite different.
→ Details of the Mt. Jiigatake East Ridge are here

Hiking Overview

• Mountain Name: Mt. Jonen

• Mountain Range: Northern Alps

• Date: February 22, 2026 (Sun)

• Weather: Clear (somewhat strong winds on the ridge)

• Course: Winter Gate → East Ridge → Mae-Jonen → Mt. Jonen (Piston)

• Distance: 23.0km

• Cumulative Elevation: +2,309m / -2,309m

• Activity time: 11 hours 21 minutes

Overall course map

Round trip from the winter gate via the Mt. Jonen East Ridge.
A long route with significant distance and elevation gain, consisting mainly of direct ascents.

Reasons for choosing this mountain

• The Mt. Jonen East Ridge route I had wanted to hike for a long time

• Favorable weather forecast

• Good weather the previous day, so a trail was expected

• Wanted to see Mt. Yari up close in the winter Northern Alps

The East Ridge is a route that only works when
weather, trail conditions, and physical stamina

all align. This time, the forecast suggested those conditions would be met.
The forecast indicated that those conditions would align.

Course conditions and impressions

▸ Winter gate to trailhead

Started in the middle of the night. Proceeded along the frozen forest road.
Parts were like a skating rink. This was deceptively dangerous.

The direct ascent continued in the darkness.
There were few switchbacks; it was just a constant climb.

▸ Trailhead to tree line

Put on 12-point crampons near the steel tower at an altitude of about 1,000m.
The trail was clear throughout, and snowshoes were not needed this time.

Gained altitude by repeating steep climbs and gentle slopes.
It was too dark to notice on the way up, but looking back, it was 'steep the whole way'.

Put on a hard shell at the tree line and switched from poles to an ice axe.

Sunrise occurred just as I passed the tree line.
The air changed completely from this point on.

▸ Mae-Jonen-dake (First Crux)

The slope steepens directly below Mae-Jonen-dake, and the elevation gain hits you all at once.
This is where your legs get worn down.

Even up to this point, the elevation gain is equivalent to an entire average mountain.
Yet, the main peak is still far away.

The summit still looked far off, but the time was within the expected range.
This time, I had set a time limit of 10:00 AM for Mt. Jonen.
If I passed that, I intended to retreat unconditionally.

I prioritized being able to return over standing on the summit.

Upon arriving, the view opens up all at once.

• Hotaka Mountain Range

• Mt. Chogatake

• Mt. Otensho

And in the distance, Mt. Norikura.

From here on was the true reward of the East Ridge.

If the Mt. Jiigatake East Ridge is a "steep climb specialist type,"
the Mt. Jonen East Ridge is an "endurance battle type."

Their characters are completely different.

▸ Mae-Jonen-dake to Mt. Jonen

Advancing along the white, packed ridge.

There is wind.
But the sky is brilliantly blue.

Near the Jonen Hut junction, a sharp shadow suddenly emerged in the depths of my view.

Mt. Yari.

At that moment, all my fatigue vanished.

The summit of Mt. Jonen was almost windless.
A grand view with the Hotaka range, Daikiret, and Mt. Yari lined up in a straight line.

▶ Click here for the record of “connecting this view via a traverse”
Panorama Ginza | Mt. Tsubakuro - Mt. Otensho - Mt. Jonen - Mt. Chogatake 2 days 1 night

Truly a “front-row seat for the Mt. Yari view”.

The clear winter air made everything stand out sharply.

The ridgeline of Mt. Chogatake, and Mt. Ontake in the distance.
The Omote-Ginza and Ura-Ginza ranges, with Mt. Tateyama and Mt. Tsurugi behind them, and even the Mt. Hakuba area.

This scenery was a view that
could only be seen on days when all conditions were met.

*The view on this day was truly magnificent, so I have compiled the panorama of the Yari-Hotaka range seen from Mt. Jonen into a separate article focused on photos.
▶︎ [Northern Alps Superb View] Panorama of Yari-Hotaka viewed from Mt. Jonen

▸ Descent

The descent is also long.

At the tree line, I switch from ice axe back to poles.
Be careful when descending the direct ascent slope.

I cannot let my guard down until the final forest road walk.
Because of the long distance, pacing your energy during the descent is truly important.

Course conditions and points of caution

✔ Some frozen sections on the forest road
✔ High physical exertion due to direct ascents
✔ The section up to Zen-Jonen is the first core challenge
✔ Significant wind impact beyond the tree line
✔ Difficulty changes drastically depending on trail conditions

*The difficulty of the East Ridge is determined by
distance × direct ascent × wind × conditions
.

Equipment decisions (this time)

• Started with boots and poles

• Switched to 12-point crampons around 1,000m elevation

• Put on hard shell at the tree line

• Used ice axe

• Did not use snowshoes (due to clear trail)

*Difficulty increases significantly immediately after snowfall or if there is no trail.

Recommended for

• Those with experience in snow mountain activities of 10 hours or more

• Those with the leg strength to endure steep direct ascents

• Those capable of making winter equipment decisions

Not recommended for

• Snow mountain beginners

• Those attempting this while unsure of their physical fitness

Reflections

The East Ridge in midwinter.

There are few technical challenges. But the distance and elevation gain are relentless.

Physical strength, weather, and the trail. If even one of these had been missing, this day would not have been possible.

And because all of them came together—
that Mt. Yari was there.

Physical strength alone is not enough.
Weather alone is not enough.

It is only when that day and that moment align that you can walk
the Mt. Jonen East Ridge.

I want to maintain this level of physical fitness for a year and walk it again next year.

Mountains are a accumulation of persistence.

I will continue to take it one step at a time, steadily.

▶ There is also a record of walking the same Mt. Jonen on a traverse
Panorama Ginza | The classic route that keeps Mt. Yari in view

Reference links

I have compiled a photo-focused summary of the
grand view of the Yari-Hotaka range seen from the summit of Mt. Jonen.

▶︎ [Northern Alps Superb View] Panorama of Yari-Hotaka viewed from Mt. Jonen

Each East Ridge has its own unique character.
I have summarized the Mt. Jiigatake East Ridge,
which left an impression with its steep climbs and knife-edge ridges, here.

▶︎ Details of the Mt. Jiigatake East Ridge are here

I mainly hike mountains in Shizuoka.
▶︎ Click here for a midwinter deep southern Alps long hike | Baratanokashira 30km round trip

▶ Click here for this month's summary