The South ridge of the Daidoushin pinnacle (大同心南稜)

Route name: Daidoushin Nanryo (大同心南稜)

Mountain:  Yatsugatake (八ヶ岳)

Map sheet:  33 [Yama-to-kougen-chizu (山と高原地図) series]

Time:  3-4 hours

Difficulty:  Grade 2+ alpine route / IV A1 crux

The Daidoushin pinnacle (大同心) is one of the most recognisable features of the Akadake-Kōsen (赤岳鉱泉) area of the Yatsugatake range. Along with its smaller sibling, the Shodoushin pinnacle (小同心), it sits high up on the face above the Uradoushin and Daidoushin gullies, below the summit of Mt Yokodake (横岳 2760m).

Its conglomerate rock is notoriously loose, so summer ascents of any of its routes cannot be seriously recommended. In winter, however, the cold temperatures hold things together a bit better and it can be climbed with a little more sang-froid. Winter brings its own challenges though, and the southern and western flanks of the pinnacle are usually exposed to bitterly cold winds. The low temperatures mandate climbing in boots and crampons, which raises the intensity level of the climbing, and with the pinnacle situated high up on the western aspect of Mt Yokodake above the Uradoushin-runze and Daidoushin-runze ice routes, the exposure on those walls is immense and thrilling.

In pure grade terms, the easiest climbing route is the 4-pitch South ridge. You’d better bring your A-game though, as the crux final pitch up the overhanging prow to the top will need both free-climbing and aid-climbing skills, as well as a cool head.

Getting there:

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 (赤岳). 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). 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.

Description:

From the Akadake-kōsen hut go up the steps near the door and take the path straight on towards the ice routes (Daidoushin runze, Uradoushin runze, Jougosawa) on the left-hand side of the face below the summit of Yokodake (横岳).

Follow the trail for about 15 minutes through the forest and you will come to a signpost pointing right into the bottom of the Daidoushin runze (大同心ルンゼ), or gully.  Here you have a choice to make in terms of how you wish to approach the start of the South ridge. There are three options as follows:

(i) Head into the Daidoushin runze and follow the stream for about 10 minutes and you will come to a trail heading up on your left along the lower section of the Daidoushin-ryo. This ridge is the normal descent ridge from the adjacent Uradoushin runze (裏同心ルンゼ) ice route, but can be easily ascended in about an hour to its apex at the foot of the Daidoushin rock pinnacle. From the top, traverse the descending ramp around the south side of the pinnacle until you reach the bottom of the first pitch of the South ridge.

(ii) Head into the Daiduoushin runze and continue up it until you reach the Ōtaki icefall. Ascend this and then continue up to the top of the runze where it swings to the left into the mixed gully behind the Daidoushin pinnacle. From here head up and left for a few metres to the bottom of the first pitch of the South ridge.

(iii) Continue along the trail to the entrance to the Uradoushin-runze and ascend this to the top of the Daidoushin-ryo. From the top, traverse the descending ramp around the south side of the pinnacle until you reach the bottom of the first pitch of the South ridge.

Route topo:

Once at the bottom of the first pitch, it’s time to gear up and start the climb. Approximate pitch descriptions are as follows:

Pitch 1: Climb the line of weakness up the rock to an in-situ anchor on a long ledge. (35m III)

Pitch 2: Traverse to climber’s left around the arête, then climb the bulgy chimney directly above to belay at an in-situ anchor on the arête itself just past a pinnacle. (35m III)

Pitch 3: Continue up for a few metres, then traverse out across a ledge to a bulge at the end. After the bulge ascend frozen turf ledges to a bolt belay at the foot of the final rock prow up the dome. (12m II)

Looking down pitch 3:

Bolt anchor before the final pitch:

(Note: If you don’t fancy the final pitch to the top, the route can be escaped from here by descending the ramp to climber’s right to the short chimney at the top of the mixed gully. The top of the pinnacle can be gained by climbing this chimney and going around on the right to loop back along to the top on easy ground.)

Looking across to the Shoudoushin pinnacle, and Mt Akadake beyond:

Pitch 4: From the belay climb steeply up on the left side of the prow for a few moves to in-situ pro. The pitch continues up the prow through rock ranging from vertical to overhanging, via a mix of aid-climbing on in-situ pitons and free-climbing in the transitions between aid sections. The exposure on this pitch is immense. Eventually you will reach an in-situ anchor at the top of the prow. (40m IV A1)

Aid-climbing up pitch 4:

Looking down from the final anchor:

From the top anchor, continue up easy mixed ground to the top of the pinnacle.

Descent:

From the top of the pinnacle you have a couple of options:

1. Descend back to the col, then climb easy mixed slopes to gain the main ridge hiking trail, and either continue left to Mt Iodake, or right over Mt Yokodake towards Mt Akadake.

2. Descend the mixed gully behind the pinnacle (in-situ rappel anchors if you need them), climb the ramp back up to the top of the Daidoushin-ryo, and descend the ridge back to the entrance of the Daidoushin-runze and on back to the hut.

Summary:

An interesting route through steep and insecure terrain on the most recognisable rock feature in the area, with some wild positions culminating in an outrageous aid pitch to the top. Whilst not for the faint-hearted, this is an excellent and challenging way to get to the top of the Daidoushin in winter!

Are you interested in climbing classic alpine and winter routes in the Japanese high mountains?

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