Raiden-yama’s Sankokunai Peak Ski Touring


Posted on Mar 23, 2020
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Posted on Mar 23, 2020

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Reading time: 4 min


5 hours





Highest point



Snow Icon | Hokkaido Wilds

Best season

Sankokunai (三国内, 970m) is a prominence on the Yoshiguni Route (吉国コース) up Raiden-yama (雷電山, 1211m) at the far western end of the Niseko Range. There's some good western-aspect skiing off the main southern ridge, so this route makes for a good alternative to going all the way to the top of Raiden-yama. Even from 970m, there'll be good views along the Niseko Range, as well as south across the Rankoshi Plains.

We visited this route on Mar 08, 2020

Route Map

Need to know details


This route up to Sankokunai on the Yoshiguni Route up Raiden-yama is on the southern side of the far western end of the Niseko Range in southern Hokkaido. The route starts at the last residential dwelling, here, in Rankoshi Town.

General notes

Via most routes up Raiden-yama’s broad southern face, skiers seeking to stand upon it’s summit will need a solid 7 hours or more for the return trip. Some of the better skiing on the mountain, however, can be had from minor peaks along the way – such as this minor peak called Sankokunai (三国内). Navigation is relatively straight forward, as the route follows a major ridge once off the forestry road.

On the descent, the main ridge offers very good skiing, as do the two major spurs on the southwestern side of the ridge. This allows for options to choose aspect depending on snow conditions – we encountered breakable suncrust on the southern aspects, but were able to get some good skiing on the more westerly aspects of the first of the two southwesterly spurs.



Route details

From the last dwelling on the road, head up a snowed in forestry road through a plantation conifer forest. Beyond the 269m point, the ridge opens up, with well-spaced old-growth trees. It’s just one ridge all the way up, so there should be little concern of getting lost when visibility is good. The final approach to the summit is steep, so check snow stability before zigagging your way up. At the top of the slope is a cornice that may need chiseling away to gain access to the summit plateau. From the broad 970m summit, there’ll be impressive views north towards Raiden-yama. This route returns the way it came. However, on the descent, slopes to the skier’s right of the ridge (to the west) also offer good skiing.

Route Timing
Up | 3.5hrs
Down | 1hrs

Most parties will get to the summit of Sankokunai in around 3 hours, but this will depend greatly on snow conditions – allow up to an extra 40 minutes or so if breaking trail through deep fresh powder.


Public transport:

There is no public transport access to this route.

By car: 

At the end of the snowclearing, there’s room for 4-5 cars to park. Do not park in the snow-clearer’s turn-around spot – park at least 50m down the road from the end of the snowclearing, so as to not be in the way. The Hokkaido Yukiyama Guidebook suggests that after heavy snowfall, snow-clearing machinery will most certainly conduct snow-clearing at some point during the day – you may need to spend up to 15 minutes shoveling out your own parking space off to the side of the road so as to not be in the way.

Physical maps
Official Topo Map: Raidenyama (雷電山) – map no. NK-54-20-11-2

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).

Snow and route safety

On the final, steep treeless approach to the summit, it would pay to check snow stability after heavy snowfall before entering the slope – it’s steep and lacks anchors.

Weather forecast weather forecast for Sakokunai
Onsen nearby

One of our favourite onsen in Rankoshi is the lovely Yusenkaku Onsen (蘭越町交流促進センター 幽泉閣, location, 500yen) next to Konbu JR train station. There are a number of indoor baths and an outdoor bath, as well as sauna and cold pool. There’s also a large relaxation space.

Extra Resources

See the write-up (in Japanese) on p. 250-251 in the Hokkaido Yukiyama Guidebook.

Guide Options

If you’d like to ski this route and/or explore other Niseko areas together with a local certified guide, get in touch with Jun Horie. He’s a Niseko-resident guide with seven years experience advanced-level ski instructing in Austria (he speaks German as well as English and Japanese). He has also guided in New Zealand and has previously led guiding operations in Hokkaido before going independent. 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. 246 (translated by Hokkaido Wilds)

Sitting right on the Japan Sea coast, Raiden-yama bears the full brunt of the winter weather. Therefore, it’s a tough mountain to climb in winter, even for seasoned veterans. That said, the brilliant-white summit and long downhill skiing descents are a big draw-card. Mid winter requires long approaches along forestry roads, breaking trail the whole way. Car parking is also limited in mid-winter. Therefore, the main season for ski mountaineering on Raiden-yama is March and April. The easily accessed minor peaks of Nikokunai and Sankokunai on the foothill ridges of Raiden-yama also offer some great skiing slopes.

Yesterday we’d had a fairly easy day out on Nishikonbu-dake (route overview here). Today was a more involved affair, with what might be five hours on the mountain. We also had two extra members join in on the trip, so make our merry troupe five in total. We parked up near the end of the road and got on our way. By the looks of things, we would be the only ones on the mountain today.

As promised in the guidebook, the first half our or so was following a forestry road through a sparse area of plantation forest. This slowly but surely transformed into more wild stands of shirakaba white birch. 

It was a Sunday, and the week preceding this had been warm. Well below zero overnight, but warm during the day. This had left a prominent suncrust on the snow on anything south-facing. Even at this early stage on the route, we knew we’d be in for some challenging skiing on the way down.

Soon enough the route started climbing in earnest. We were soon zig-zagging up a wide ridge with well-spaced trees. With good fresh snowfall, this entire ridge would be bliss for skiing.

As the group climbed up, we soon found the cloud layer had forecast for around 1000m. The visibility was still good, so the mist just added a layer of mystery and mystique to the route.

We soon arrived at the base of the final short but steep approach to the summit of the Sankokunai peak. The snow seemed firm underfoot, and we made it up to the summit without any chiseling of cornices, as suggested in the guidebook. Just off the summit, we dug a large hole for all of us to hunker down in out of the wind for a quick lunch.

On the descent after lunch, we were all remarking about how amazing it would be if the snow was in better condition. The grabby breakable crust was making things tough going for us. On a normal mid-winter’s day – or indeed a full-blown spring day – the descent would have been incredible. We opted to ski the upper of the two large western spurs off the main ridge. It was bushy on the northwestern side of the spur, but there was decent enough skiing down the ridgeline.

Skiing the spur meant that we were now at the valley floor, and had a long, ever-so-slightly descending traverse to get back to our skintrack low on the main ridge. This would have been quick and easy, however unfortunately the snow was now the dreaded stoppu-yuki as they call it in Japanese – wet and slow. This slowed progress even as we joined with the main uptrack.

We limped back to the car, but we did so with great smiles on our faces, happy to have spent a good morning out on the mountain.

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Comments | Queries | Reports

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