Route name: Akadake Tengu ridge (赤岳天狗尾根)
Mountain: Yatsugatake (八ヶ岳)
Map sheet: 32 [Yama-to-kougen-chizu (山と高原地図) series]
Time: 1-2 days
Difficulty: Grade 1 alpine route / III+ crux
If the presence of the Akadake-Kousen hut is what makes the North side of Akadake such a popular winter playground, perhaps it is the absence of any such development that makes the South side of Akadake so remote and alluring. You will find no crowds here; in fact, you will most likely see nobody at all.
The unmanned unheated Deai-goya hut serves as erstwhile basecamp to the ice and alpine climbing on this wilder end of the massif. It is well-situated, for just 10 minutes further up the valley lies the foot of the famous Tengu ridge.
Rising over 1200m from the valley floor to its terminus just short of the summit of Akadake, the Tengu ridge is a big outing, and reserves most of its difficulties for its upper reaches. At the point where the tree cover ends, the ridge rears up in a series of rocky pinnacles and gendarmes that are absolutely stunning when viewed in profile from one of the adjacent ridgelines. The last two pinnacles form the climax, and together they constitute the eponymous Tengu.
Despite only moderate technical difficulties, if you get there too early in the season deep untracked snow can endow the Tengu ridge with Himalayan proportions. But if you can hit it in good conditions, this elegant ridgeline constitutes the very essence of classic winter mountaineering.
If travelling by public transport from Tokyo, take the Super Azusa Limited Express train from Shinjuku to Kobuchizawa (小淵沢), and then change to the local Koumi line train. Get off at the small resort village of Kiyosato (清里), and then take a taxi 10 minutes up the road to the Utsukushimori car park (美し森駐車場).
If travelling by car from Tokyo, take the Chuo Expressway and exit at Nagasaka IC (長坂IC). Turn left onto route 32, go under the Expressway and continue a short way to a large crossroads, and then turn left onto route 28. Route 28 will take you all the way to Kiyosato station. Follow the road round to the left just below the station and head up the hill on route 11 towards Utsukushimori-yama (美し森山). At the traffic lights continue straight as the road turns into route 615. You will soon reach the Utsukushimori car park (美し森駐車場) on your left. This is the trailhead for this outing.
(i) The approach
Take the small flight of concrete stairs behind the building in the car park, and then turn left and start walking up the snow-covered road.
After about an hour you will reach a sort of junction where a trail heads off diagonally downhill on the left, but you should keep contouring along on the road. Soon the road will turn into a hiking trail through the forest and up the river past a number of concrete dams.
Eventually you will arrive at the unmanned Deai-goya hut. In good crisp conditions with a trace in place this can be done in about 1.5 hours, but it can take up to 3 hours in deeper snow. Many people choose to split this climb into two days by spending the night here and getting an early start to climb the ridge the following morning. Unless you are very confident in your speed and fitness, and have good snow conditions, this might be your recommended strategy for the Tengu ridge.
(ii) The climb
Continue on past the hut for about 5-10 minutes and you will reach a fork in the river, where the Akadake-sawa comes in from the right. This place is the Akadake-sawa-deai, and the Tengu ridge rises from this fork. You need to cross the river here, but don’t go up onto the ridge just yet. Instead, continue up the Akadake-sawa.
After about 10-15 minutes you will see a re-entrant on your left. Climb this to gain the Tengu ridge, and then start ascending the lower ridge.
The first hour climbs up through the trees, initially at a gentle gradient and gradually steepening. Eventually you will pop out of the trees onto a narrow open section of ridgeline with excellent views along the ridge to the first rocky pinnacles in the distance, and to the East faces and ridges of Gongendake and Asahidake to your left.
After a short descent you will once again be in tree cover. The gradient begins to steepen in earnest now, and after some time you will arrive at the beginning of the difficulties.
The first obstacle on the ridge is a curious rock called Kani-no-hasami (カニのハサミ), or the Crab Scissors rocks, named for their resemblance to a crab’s pincers. Go around to the left of these along a rocky ledge, and then climb a 10m rock face to regain the ridge.
The next obstacle is a large rock wall about 30 high. This can be climbed on the left, but most people turn this on the right. A line of fixed rope heads out along a very narrow and exposed ledge, with some awkward moves on rock at the end of it to gain a steep snow gully. Climb this gully to the top and then continue along the ridgeline.
The next large pinnacle is turned via a ledge on the left followed by a steep but well-featured climb up a rocky face.
From the top of this, head around to the right and you will at last be confronted with your first view of the famous Dai-Tengu (大天狗) and Ko-Tengu (小天狗) pinnacles up ahead.
When you reach the Dai-Tengu, traverse across the angled snow slope and build an anchor on the tree closest to the rock face at its right edge. From here climb a single pitch of III+ rock to gain the right side of the Dai-Tengu. There are in-situ pitons on this rock wall, and a bolt anchor at the top of it.
From the anchor, continue around the right side of the Dai-Tengu to the col between it and the striking Ko-Tengu.
To get past the Ko-Tengu, traverse out on ledges on its left side, and then pick the easiest line up the steep rocky slope to arrive at the foot of the pinnacle on its far side. If you wish to climb to the top of the Ko-Tengu, there is an in-situ anchor on its summit to facilitate descent.
Now just continue up the corniced ridgeline a short way until you reach the end of the Tengu ridge and the junction with the hiking trail. The 2899m summit of Akadake lies about 40 minutes further up the hiking trail, with chains and ladders in all the most exposed sections along the way.
From the summit of Akadake there are a couple of options for returning to Utsukushimori car park:
1. Re-trace your steps back along the hiking trail for about 10 minutes until you reach a junction, with a trail heading off to climber’s left. This is the Shinkyoji ridge trail (真教寺尾根), and will get you back to Utsukushimori in around 4 hours in good snow conditions. The first hour is very steep, with sections of down-climbing and chains. The rest is more amenable, with an initial uphill to the top of Ushikubi-yama (牛首山 2280m), followed by seemingly endless downhill, past the ski resort at the bottom of the ridge, through the forest and then down a series of wooden stairs that eventually deposit you at the car park.
2. Re-trace your steps all the way back to the top of the Tengu ridge itself, and then continue scrambling along the precipitous hiking trail, and down a steep rocky gully. At the bottom of the gully the ridge levels off a bit. Carry on a short way to the Kiretto-goya hut (キレット小屋), then continue a bit further until you reach the minor summit of the Tsurune (ツルネ). From here take the Tsurune East ridge (ツルネ東稜下降) all the way back down, then continue until you reach the Deai-goya hut. From there you just need to hike back out the way you came in to the road and on eventually to the car park.
In unconsolidated conditions this would be an extremely serious and physical outing, and is best avoided. But in good conditions, generally later in the winter season, it is a top-draw classic winter mountaineering outing up one of the most striking and beautiful ridgelines on Akadake. The technical difficulties are moderate, and a light rack of slings and carabiners will suffice. The main challenges centre around navigation and the enormous scale of this route. Completing it in a one-day round-trip from the car park is a wonderful challenge, and a very big physical undertaking.
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