A Long-Awaited Book on the Hidaka Mountains Has Been Published
Back in the 1970s and 80s, there were large-format photo collections of the Hidaka Mountains, some of which even included aerial photography. I used to study those photographs intently every day for winter traverse terrain research. Given that the region has no established hiking trails, the only references we had were either crumpled, handwritten trip reports left in the clubroom or the club bulletins, which were at least printed and easier to read.
Even now, after all these years, I’m happy to see that the innermost parts of the Hidaka range remain untouched and pristine. The book also documents the background of the ill-fated plan for a Hidaka crossing road, which was eventually abandoned.
In truth, it’s impossible to create the kind of hiking guide that most people expect for a place like the deep Hidaka?so remote that even experienced mountaineers can’t easily access it. I can’t recall another chance like this when such a comprehensive book on the Hidaka Mountains has been published.
I was fortunate enough to contribute to this special volume.
As a narrative of Hidaka’s story, it includes graphic-rich presentations of early expedition accounts from pioneers of the Hokkaido University Alpine Club’s formative years (Nobuyuki Sudo, Shugoro Ito, Osamu Aikawa), reports on accidents in Koikaku-sawa and Ju-no-sawa, the bear attack involving Fukuoka University, and the journeys of painter Chokkou Sakamoto.
Three authors?Akio Koizumi, Satoru Yoneyama, and Norihiko Matsubara?wrote beautifully about the profound appeal of the Hidaka Mountains in both winter and summer. It also includes detailed descriptions of the nearly superhuman winter long-distance traverses carried out by young alumni in the 21st century, along with the origins and development of the igloo technique, which has become a hallmark of the Hokkaido University Alpine Club.
In 1990, while simultaneously working on my graduation thesis, I hand-drew a bird’s-eye map of the Hidaka range as a large fold-out supplement to the 13th issue of the club’s bulletin. I’m delighted that this piece has been republished here, now beautifully colored 35 years later. As I gaze upon it, memories come flooding back?memories of walking along each of those drawn lines with great care and affection.
The book also includes richly illustrated articles on geology, topography, and the flora of Mt. Apoi. There are fascinating explorations of two ancient mountain routes in the southern Hidaka region. Altogether, it’s a multifaceted book themed around “The Hidaka Mountains and People.”
On the cover and at the beginning of the book are brand-new photographs by Kenji Ito, an alumnus of the alpine ski team. Look closely?you might spot a bear walking across a snowfield in one of them.
It’s a large-format book, yet light in weight and pleasing to the touch. Available not only at bookstores but also on Amazon. Release date: April 27.
Published by Kyodo Bunka-sha First Edition: May 15, 2025 Editor and Author: Shinichi Kurokawa Price: 2,700 yen + tax
70 Igloo-Themed Trip Reports on Yamareco So Far This Season
A search for mountain trip reports on Yamareco with the word “イグルー” (igloo) in the title yielded a surprising number?70 entries already this season. If we include those who didn’t put it in the title, there are far too many to count. Clearly, igloo-building has become much more common among winter mountaineers.
Documenting Skill Progression Through Repeated Practice
Some users have compiled “summary articles” using photos to document their own igloo-building journey?starting from early attempts when they struggled to build a roof, to gradually improving over multiple tries. These are very interesting to read. One person wrote that they kept at it not because they had to, but because it was simply fun to build. I couldn’t agree more.
Although these two users never attended any official workshops, it’s clear from their photos that their skills have significantly improved:
Skills Gained Through Personal Trial and Error Are the Ones That Stick
At igloo-building workshops, I often demonstrate how to build one in 40 minutes. But that’s really just to show that “yes, it is possible to make one.” Ultimately, the skills that truly stick are the ones you gain by trying yourself, failing, thinking through the problem, and discovering your own tricks that make it work. That feeling of success is the most important part of learning.
Even if you’re taught every little step in advance, it often doesn’t stick, and it tends to lead to a passive, “waiting for instructions” mindset. The best approach is to encourage people to think and experiment on their own.
I recently read a book by Makoto Shinohara that echoed this same idea. Though I probably wouldn’t have picked it up based on the title alone, I found his Twitter commentary on energy policy and agricultural self-sufficiency during these times of change fascinating. His book provided great insights into how people learn?and this is exactly how learning works.
Igloo-Building Has Huge Potential for Personal Growth
Unlike snow caves, which anyone can dig, igloo-building tends to show a lot of individual variation. That’s what makes it so enjoyable?there’s plenty of room for creativity and personal growth, making it incredibly rewarding. It’s an activity full of charm.
Mid-Season Summary of My Own Igloo Activities
So far this season, I’ve held 10 workshops:
2 at the Matsumoto City Mountain Forum
2 with university mountaineering clubs
3 with mountaineering associations
3 with friends or small groups
In addition, I’ve spent 6 nights in igloos on my own mountain trips. I still have two long expeditions planned for the holiday period, and I expect to spend 4 or 5 more nights in igloos (I’ve been putting it off, but maybe I’ll finally head out tomorrow). This winter, I even had the intense experience of building igloos in the worst storm conditions I’ve ever faced, adding to my experience all the more.
Igloo Night in the Storm Zone at Norikura-dake (Elevation 2,640m)
Crossing Norikura-dake on a Unique Route in Fierce Winds
During a spring weather pattern with intense winds, I traversed Norikura-dake via a unique route. My partner’s long-established route design follows a ridge leading directly up to the sharp peak of Eboshi-dake. We spent nearly ten hours breaking trail through beautiful coniferous forests before reaching the volcanic plateau at the summit, where we entered the storm zone. A tent (not that we had one) would have been blown away for sure.
Roof Collapsing in the Wind → Ski Roof Construction
The Norikura Skyline road was covered in blue ice, requiring ice screws for traction. We found a snowdrift with packable snow deep enough for a saw to cut through, and we began constructing our igloo there. The first row of blocks was easy to carve, but beneath that was solid blue ice. We widened the block supply area, transported them, and stacked them.
Around the third row, we attempted to place long blocks as a roof, but the wind knocked them down the moment we looked away. Every time they fell, they snapped in half. After this happened three times, we switched to using skis and poles as beams. That worked like a charm, and the roof was up in no time.
Double Layering the Windward Side to Seal Gaps
Unlike usual, I couldn’t afford to leisurely fill in the gaps. On the windward side, I added an extra exterior wall for a double-thickness defense. Even so, the powder snow carried by the ground blizzard kept infiltrating through the cracks?just like what happened to me on Mt. Fuji before.
My partner was busy collecting blocks at first, but soon, his face was covered in frost formations (sastrugi), and his glasses became useless. The wind-driven snow kept striking his eyes, blinding him from looking upwind. I had him wait under a bivy sack, though even that was a struggle to keep from being blown away.
Bivy sack Sticking to the Wall Thanks to Bernoulli’s Principle
Inside the igloo, snow was still blowing in from the gaps. But when we wrapped ourselves in a bivy sack, something curious happened?it clung to the walls without any support. The fast-moving wind outside created lower pressure compared to the inside, making the tarp stick to the surface. It was a real-life demonstration of Bernoulli’s principle?the same aerodynamic effect that makes an airplane wing generate lift. I’ve been interested in aeronautical engineering since middle school, so I recognized it immediately.
Bernoulli’s effect lasted until morning. But I sure wished the wind would die down sooner…
The Igloo Filled with Snow, but at Least the Wind Was Just Noise
The snow that blew in between the walls and the bivy sack kept creeping inside. Snow piled up on both sides, covered my sleeping bag, and eventually fell underneath me, melted from my body heat, and turned into a freezing puddle. I shivered all night, but it wasn’t life-threatening.
The wind occasionally slammed against the igloo like a powerful punch. I had simulated an emergency plan in case the walls collapsed, but fortunately, they held.
I lit my stove on my lap, drank multiple cups of milk tea, and finished both dinner and breakfast. By morning, the wind was still howling. I stuffed my soaking wet sleeping bag into my backpack, pinched my nose, and made a break for the treeline. The visibility was a blessing. Under clear but violently windy skies, we descended to safety. The trip was only half of what we planned, but given the conditions, that was inevitable. More than anything, I felt deeply satisfied that we managed to push through.
Building an Igloo in Strong Winds with Minimal Snow
I had encountered similar conditions before on Mt. Fuji. There, with little snow, we had to stack flimsy blocks while an endless stream of granular snow particles tumbled through the gaps. That time, my companions swore they were done with igloos for good.
This time, the bivy sack inside made it somewhat bearable, though certainly not comfortable. A larger tarp might have helped if we had stretched it over the exterior, but anchoring it on blue ice would have required screws, and the wind would likely have shredded it anyway.
Of course, the best option would be to avoid camping in such places. But mountains don’t always follow orders. When faced with the unexpected, you just have to make do with what you have.
マッキンタイアと聴いたマリアンヌ・フェイスフルの歌（Broken Englishかな？）、トランゴで落っこちた後、ロレタンが聴かせてくれたダイア・ストレイツの歌（たぶん「Brothers In Arms」）。聴いてみると当時に時代を引っ張り戻してくれる。ポーランド人の名前や地名の発音しづらさが面白くてポーランド語初級教本やポーランドの地図と略史なども読みながら読み進めた。ポーランド、行ってみたくなってきました。
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久しぶりの、日高山脈本が出版されました
