Kotoninupuri and Osappenupuri Ski Touring

コトニヌプリ・オサッペヌプリ | Kutunnupuri/Osatpenupuri

Posted on Mar 14, 2021
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Posted on Mar 14, 2021
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10km

Distance

5 hours

Time

572m

Ascent

964m

Highest point

4.5/10
Difficulty
Snow Icon | Hokkaido Wilds
Jan-Mar

Best season

Bordering on the Akan-Mashu National Park 阿寒摩周国立公園, high up on the Lake Kussharo caldera rim, Kotoninupuri コトニヌプリ (952m) and Osappenupuri オサッペヌプリ (860m) are perfect for inspiring views across Lake Kussharo. The forest on its own is worth a visit - the area is characteristic of the Akan flora, with ancient trees, moss hanging off the branches. For an area this far east, there's still plenty of good quality snow, and the descent from Kotoninupuri is a blast. If short for time, we'd recommend just a quick up-and-back to Kotoninupuri.

We visited this route on Feb 21, 2021

Last updated Apr 2, 2021

Route Map

Need to know details

Location

Kotoninupuri and Osappenupuri are peaks sitting on the southern end of the Lake Kussharo caldera in far eastern Hokkaido. With Tsubetsu Pass closed over winter, the route starts from just behind the gorgeous Tsubetsu Onsen, here. 4.5

General notes

With a relative abundance of blue-sky days, eastern Hokkaido is a ski tourer’s dream, and this route is a relatively easy way to make the most of that. The forest is classic Akan-Mashu National Park forest, with a somewhat prehistoric feel to it. Moss hanging from trees, old-growth stands of towering trees, seemingly untouched by human activity. There’s not even a summer hiking trail, and no peak markers.

Hut
None
Route details

Park up either to the front or back of Tsubetsu Onsen, and start skinning due east along the forestry road, on the northern side of Shichi-no-sawa creek 七ノ沢. Stay on this northern (left) side of the river until around 570m in altitude – about 2.4km. There’s an old broken bridge around here crossing the Kamisato creek 上里川, which serves as a support for a snowbridge over the river. Climb up a spur on the southern side of the river, heading east southeast up towards a broadening forested slope. Keep heading in a general southeast direction, to arrive at a saddle just north of the Osappenupuri summit. From the saddle it’s a short walk south to the summit of Osappenupuri. From the summit there’s not really much of a view, but the forest across the saddle is really quite lovely. Now head direct north back to the saddle and enjoy the gradual climb up the broad ridge to Kotoninupuri. From the actual Kotoninupuri summit, there’s not a particularly great view, so drop down to the east just below the summit for a grand view of Lake Kussharo. Once you’ve had your fill of the view, head back up to the summit. The descent from the summit back down to the forestry road is a fun consistent slope west from the summit. Part way down, it’ll join back up with the uptrack. Watch out for downed trees and barely-buried branches. Back at the skintrack, follow it back to the forestry road and then back down to the onsen. The forestry road is just steep enough to ski down in the skintrack, with just a few sections of poling.

Route Timing
Up | 3hrs
Down | 1hrs

For the full loop, expect about four to five hours, as there is a fair bit of very gradual climbing. For a shorter trip, consider passing on Osappenupuri and just head straight for Kotoninupuri. In this case, expect about three and a half hours total.

Transport

Public transport:

This route is not accessible by public transport.

By car:

Tsubetsu Onsen (location) is about 25km southeast from central Tsubetsu. Note that Tsubetsu Pass 津別峠 is not open in winter. If approaching from the Teshikaga or Lake Kussharo side, expect about one hour to drive around to Tsubetsu via Bihoro.

Physical maps
Official Topo Map: Kotoninupuri (コトニヌプリ) – map no. NK-55-31-15-2

NOTE: The official 1/25000 topo map(s) above can be purchased for 350yen from Kinokuniya bookstore next to Sapporo Station or online (in Japanese).

Aspect
The main aspect skiers are exposed to on the descent and/or ascent is West. Therefore, keep an eye on the weather forecast a few days ahead of your trip to monitor wind, snow, and temperature. Unfortunately there are no avalanche information services for recreational backcountry users in this immediate area (but see the JAN reports and Furano Avalanche Center for sporadic observations eslewhere in Hokkaido).

Snow and
route safety

Navigation on this route can be a little tricky at times, with a gradual approach on broad slopes mostly in the forest. Also note that despite the low altitude, visitors should expect very cold temperatures and come suitably prepared.

Kotoninupuri and Osappenupuri Ski Touring Difficulty Rating

Category

Grade

Points

Strenuousness

Vertical Gain

C

30

Time ascending

C

3

Technicality

Altitude

B

6

Hazards

D

0

Navigation

C

6

Totals

45/100

GRADES range from A (very difficult) to D (easy).  More details here. Rating rubric adapted from Hokkaido Yukiyama Guidebook 北海道雪山ガイド.

Weather forecast

Windy.com weather forecast for Kotoninupuri/Osappenupuri
Onsen nearby

The route starts and finishes from the Tsubetsu Onsen Lamp-no-Yado 津別温泉ランプの宿森つべつ (location, 600yen). This is a gorgeous onsen tucked into the forest, with relaxing outdoor bathing too. There’s an attached restaurant.

Extra Resources

See the detailed write-up in the Hokkaido Yukiyama Guidebook, p. 404-407.

Guide Options

If you’d like to ski this route and/or explore other areas of Eastern Hokkaido or Shiretoko together with a local certified guide, get in touch with Takao Miyashita. He’s a born-and-bred Hokkaido-based guide. From a young age he cut his teeth on peaks including those in far eastern Hokkaido. He has multiple 6,000m-plus peak international expeditions under his belt (including a ski descent from 7,400m on Mt. Manaslu, Nepal). He is one of the leading senior figures in the local guiding and outdoor associations here in Hokkaido and Japan. See a full list of English-speaking Hokkaido Mountain Guides Association (HMGA) guides on the HMGA website here

Show Full Route Notes Close Route Notes

Route Trip Notes

Route blurb from the Hokkaido Yukiyama Guide (2015), p. 404 (translated by Hokkaido Wilds)

Both peaks are on the Kussharo caldera rim, with Tsubetsu Pass just to the north. Just a little further north still was the old Tsubetsu ski area. There’s no summer trail, but these peaks are often climbed by locals. They’re relatively easy to climb, the views are great, and there’s also good skiing. This route takes in two peaks in a loop, connected by the ridge. And who can resist a ski tour starting from an onsen?

Akan-Mashu National Park. It’s a rather hard nut to crack in winter. One would naturally be drawn to the big names of Meakan-dake or Oakan-dake. But snow cover is not guaranteed there, especially up high. We were keen to get back out east this season, however, so settled on ticking off another couple of routes from the venerable Hokkaido Yukiyama Guidebook. Those two routes were located on the southern end of the Lake Kussharo caldera, so would at least give us a good feel for the snow conditions closer to the Akan volcanoes, without being too committing.

Another big drawcard to get out east was to visit our friend Gerry. In Kitami City since part way through 2020, we were keen share a bit of adventure with her in her new back yard.

We’d spent the last couple of days in Furano (where Nisade put us up at Fenix Furano), and had arrived at our AirBnB in Bihoro the previous day.

We arranged to meet Gerry early at the trailhead for Kotoninupuri, and were away from the trailhead just before 8am. Despite the early start, the Tsubetsu Onsen carpark was almost full though, giving a glimpse of how well-loved this area is, tucked away in a quiet valley here in eastern Hokkaido.

For almost an hour, we skinned along the slightly ascending forestry road next to the river. Ahead of us were a set of ski tracks and it was clear some snowshoers were up ahead of us too. There was plenty of snow, which was somewhat of a surprise. On the drive into the valley, the surrounding farmland and hills seemed to be worryingly devoid of snow. But up here, it was another world. It wasn’t cold. Soon we were shedding layers.

We soon caught up to the showshoers – an older couple. They were tentatively planning on heading all the way up to the Kotoninupuri summit.

“We got a late start though,” the gentleman said. “And we’re not confident of the weather, so we’ll probably call it a day here. We’ll take a break and decide.”

We carried on and were soon at the 570m altitude mark on the map, so started scouting out a good spot to cross the river and start climbing in earnest towards the caldera rim. We’re not 100% sure if what we crossed was indeed the “broken bridge” mentioned in the guidebook. But what ever it was, it was solid, and made for easy crossing, albeit a bit of a side-step down and up again.

The forest was quintessential Akan-Mashu National Park. While we weren’t actually within the park boundaries at this point, this forest seems to have been spared logging in the past. Grand old trees towered above us as we made our way up the narrow spur and then wide slope towards the saddle between Osappenupuri and Kotoninupuri.

The long climbing traverse up to the saddle wasn’t steep. This loop route via both peaks was clearly more of a walk than a ski. Already it was clear that if it was more the skiing one was after, a quick up-and-back to Kotoninupuri would be the way to go.

But we were in no hurry, and once we were on the saddle, the forest was again quite spectacular. All the trees were coated in a hard ice layer. Clearly a few days ago there’d been freezing rain in the area, encasing bark and pine needles in clear ice.

High above us, a white-tailed eagle soared on up-currents.

From the saddle, it wasn’t far to the Osappenupuri summit. Once there, however, we didn’t hang around very long. There was an icy wind blowing, and there wasn’t any view, apart from a vague view of the next objective, Kotoninupuri. We returned down to the saddle, and skinned up towards Kotoninupuri through gorgeous old forest, now just within the Akan-Mashu National Park border.

Just before the Kotoninupuri summit, I noticed that there was a small clearing just below it. I shuffled down to the clearing, and sure enough, this gave us an unobstructed view of the southern end of Lake Kussharo. It was frozen, covered with a layer of white snow. Haidee and I had seen Lake Kussharo in the winter from the northern end (from Makoto-yama) before, but this was the first time we’d seen it from up high at the southern end.

Indeed, the Kotoninupuri summit itself didn’t really lend itself to great views of the lake – the large trees surrounding the summit blocked things out a bit. Skirting along the summit ridge however, we found spaces in the trees allowing more views, including of the island in the middle of the lake.

After skinning a ways down from the summit on the mellow summit plateau, we ripped off our skins and prepared for the descent.

The descent from the summit plateau to the forestry road was unexpectedly good. With suitably well spaced trees and a good gradient, the skiing was very good. The snow was a strange sort of only-just-breakable crust with a decent layer of fresh snow on top. While we were not forced into survival skiing, it wasn’t brain-dead skiing either. We need to get back to this area in early or mid-February to sample some decent eastern Hokkaido powder.

Once back on the forestry road, it was a mix of easy poling and a bit of skating on the hard-packed surface. We weren’t tempted to put the skins back on, but that may have been a different story had the snow been fresher and deeper.

Once back at the onsen, we did, of course, avail ourselves of the facilities. It was one of the better onsen I’d been to out this way in eastern Hokkaido – lovely forest surrounds and wonderfully quiet.

Comments | Queries | Reports

Done this route to Kotoninupuri/Osappenupuri, or others nearby? Thinking of doing it? Please post any feedback, reports, or queries here. Thanks!

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Kotoninupuri and Osappenupuri Ski Touring Difficulty Rating

Category

Grade

Points

Strenuousness

Vertical Gain

C

30

Time ascending

C

3

Technicality

Altitude

B

6

Hazards

D

0

Navigation

C

6

Totals

45/100

GRADES range from A (very difficult) to D (easy). Hazards include exposure to avalanche and fall risk. More details here. Rating rubric adapted from Hokkaido Yukiyama Guidebook 北海道雪山ガイド.