Route name: Nakayama-one (中山尾根)
Mountain: Yokodake (横岳) in the Yatsugatake range (八ヶ岳)
Map sheet: 32 [Yama-to-kougen-chizu (山と高原地図) series]
Time: 4-6 hours
Length: 9 pitches
Difficulty: Grade 2 alpine route / IV+ crux
The Nakayama ridge is a stunning mixed arête of snow and rock that rears up steeply through the southern end of the west face of Mt Yoko in 9 pitches, finding its terminus near the top of the minor peak of Hinodake (日の岳). Slightly harder and longer than the Shu-ryo (主稜) on neighbouring Mt Aka (赤岳), this route is a local classic and well sought-after, so expect other parties on the route if climbing on a weekend. Its two rock steps present the main challenges in full winter conditions, but the angle and exposure are fairly consistent all the way to the top.
The route is generally exposed to the prevailing winds, and gets little sun until around midday. With close-up views across to both Mt Aka and Mt Amida (阿弥陀岳), as well as a clear view along the length of the famous west face of Mt Yoko, the Nakayama ridge provides some of the most spectacular positions in the area.
If travelling from Tokyo, take a Super Azusa Limited Express train from Shinjuku to Chino (approx. 2.5 hours). Outside the JR station at Chino take a bus to Minotoguchi (美濃戸口, approx. 45 minutes). This is the gateway to the Akadake-kōsen side of Yatsugatake. From the carpark start hiking up the trail that is signposted to Akadake. The walk-in takes up to 3 hours by map time. It is split into 3 stages. The first hour brings you past a series of buildings and on a little further to a hut with a water source, which makes a good resting point for 5 minutes. The trail splits here, with the right fork going up Minami-sawa (南沢) to the Gyouja-goya hut (行者小屋). This is the quickest approach if you are planning a single day round-trip ascent. If you are planning on staying in the Akadake-kōsen hut, you need to take the left fork up Kita-sawa (北沢). The next hour follows the rough dirt road until it finishes at a bridge across the sawa. From the other side the path narrows and meanders alongside the sawa for another hour or so until you reach the hut at Akadake-kōsen. This hut and its campground serve as basecamp for all the routes in the area, as well as for the popular Ice Candy artificial ice wall.
As you exit the Akadake-kōsen hut by the front door turn right and follow the trail to the end of the hut and then up through the forest. After about half an hour and a couple of zigzags you will arrive at a signpost on a small flat area. This is the access point for the Nakayama ridge. This could turn out to be a long day, so aim to arrive here by sunrise.
Enter the forest behind the sign and head uphill, doing your best to follow the occasional tiny coloured tape markers on tree branches.
The further you go, the steeper the angle becomes until eventually after about half an hour you will exit treeline onto a small mixed arete that leads up to the base of the first rock step.
Pitch 1: You will notice a line of petzl bolts leading directly up the front of the rock step. This is the summer line of ascent and is quite smooth and slabby, very problematic in crampons and gloves. The usual start in winter is to traverse about 8-10m to the right and enter a chimney that leads up leftwards to join the petzl bolts higher up. The first 5m is unprotected until you reach the first bolt, but from then onwards there are bolts at regular intervals. Finish at an anchor on a small ledge. (35m III+)
Pitch 2: From the belay ledge, climb left up a blank wall past a petzl bolt to gain a small tree. Continue up the steep snowy face, from the solace of one small tree to the next, until you gain the arete. Belay at a large tree just off the arete below a small rock step. (40m III+)
Pitch 3-5: Continue up the arete on a mix of snow and rock scrambling, belaying on trees as necessary, until you reach the anchor at the foot of the second rock step.
Pitch 6: Climb steeply up the initial chimney until you reach a small scoop. Now head up the crack on the left, making a series of very steep layback moves to gain the top. (50m IV+)
Pitch 7-9: Continue up the arete on steep mixed ground until you pull over onto a small pulpit on a sharp pinnacle that marks the top of the arete, at the start of the obvious traverse band.
From here you have the option to continue to the summit of Hinodake via another grade IV pitch, but most teams opt to traverse across the obvious and airy band to gain the normal hiking trail that leads down to the Jizo col between Mt Yoko and Mt Aka. The views from this area are simply spectacular!
Once at the hiking trail, you have several options:
(i) The quickest way to get back down is to descend the hiking trail down the Jizo-one ridge to the Gyouja-goya hut.
(ii) You could head north to traverse Mt Yoko over to Mt Io, and then descend from there back to the Akadake-kōsen hut.
(iii) If you wish to summit the highest peak in the Yatsugatake range, simply continue southwards on the trail and up to the top of 2899m Mt Aka. Continue over the summit and down to the Bunzaburo ridge trail and follow it all the way down to the Gyouja-goya hut.
A fantastic route with varied climbing, sustained exposure and amazing views of the surrounding peaks and faces. Bring full winter gear including double ropes and a small trad rack, dress for severe cold, and enjoy every bit of this local gem!
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