The Daidoushin-ryo (大同心稜) on Mt Yatsugatake (八ヶ岳)

Route name:  Daidoushin-ryo (大同心稜)

Mountain:  Yatsugatake (八ヶ岳)

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

Time:  1 day

Difficulty:  Grade 1 alpine route with some rock scrambling

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).

For the less adventurous its rocky summit can be accessed via a short and easy scramble down from the summit ridge just north of Yokodake’s highpoint. For hardcore climbers there are several routes up the vertical cliffs of its western and southern aspects.

For those of you operating somewhere in between, there also exists a fine route from the Akadake-Kōsen hut, which pulls together many of the skills needed for winter climbing but at a moderate difficulty level. This makes it a perfect choice of route for those looking to make the step up from winter hiking trails into some of the easier winter variation routes.

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:

As you exit the Akadake-kōsen hut by the front door you have 3 paths to choose from. Left takes you to the descent trail back to Minotoguchi; right takes you towards the Nakayama-one (中山尾根) and beyond to Akadake; straight on provides access to the ice routes (Daidoushin runze, Uradoushin runze, Jougosawa) on the left-hand side of the face below the summit of Yokodake (横岳). To get to the foot of the Daidoushin-ryo you need the latter path.

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.  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.

At this point the trail looks like it is going to vanish into a vertical rock wall, but closer inspection reveals a ledge leading round the side and gently dropping down into the top of the Daidoushin runze.

From the end of this ledge the route bends sharply to the left behind the Daidoushin pinnacle.  It’s a spectacular place, seemingly right in the bowels of the mountain. If there is a lot of snow on the ground, you’ll be able to crampon up a steep snow slope here to access the top of the pinnacle from behind.  However, in less banked-out conditions you’ll find a steep rocky gully, and the route weaves its way up this mixed terrain via a series of indistinct ledges zig-zagging up to a constriction at the top. There are in-situ pitons and bolts all the way up this section if you want to rope up.

Stem your way up this short chimney to reach a comfortable terrace. There are anchors at the bottom and top of the short chimney, and many Japanese guides use this area as a training ground for their clients.

The views back down and all around are stunning.

From the large terrace, traverse across to your left and ascend a ramp followed by an easy scramble up a steeper face to gain the short ridge that connects the summit of the Daidoushin pinnacle with the main ridge and Yokodake. From here a short walk will bring you to the flat rocky summit of the pinnacle.

Continuation and descent:

From the summit of the Daidoushin pinnacle it is just an easy 10-minute scramble up to the main ridge and the hiking trail. From here you have a couple of options to continue.

Heading left will take you over to the broad summit of Mt Iodake (硫黄岳), about 30 minutes away, from where you can easily hike back down to the Akadake-kōsen hut in another hour.

For a more interesting continuation, I recommend turning right and ascending the rocky ridgeline to the summit of Mt Yokodake, just 15-20 minutes away.  From there continue on carefully along the ridgeline to the Jizo col, and beyond there up to the spectacular summit of Mt Akadake (2899m).

Yokodake summit:

On the main ridgeline:

Approaching Akadake:

Sun burst behind Amidadake:

Ascent of Akadake:

Akadake summit:

Descend off the other side of Akadake down to the Bunzaburo ridge (文三郎尾根), and follow this all the way down to the Gyouja-goya hut and on back to the Akadake-kōsen hut.

Summary:

This is a first-rate introductory itinerary for anyone wishing to make the transition up from winter hiking to more technical winter climbs, with thrills and exposure at a moderate difficulty level.  It will also give you a unique insight into the topography of the cliffs above the Akadake-kōsen.  Continuing over Akadake is recommended, but will make it quite a long day, so be sure of your fitness level.