Route Name: Uradoushin runze (裏同心ルンゼ)
Mountain: Yokodake (横岳 Yatsugatake massif)
Time: 3 hours to top of descent ridge (Daidoushin-ryo)
Difficulty: A grade 2- winter alpine route (WI3/4)
Take a Super Azusa express train from Shinjuku to Chino (approx. 3 hours). Outside the JR station at Chino take a bus to Minotoguchi (approx. 1 hour). This is the gateway to the Akadakekōsen side of Yatsugatake. From the carpark start hiking up the trail that is signposted to Akadake (赤岳). The walk-in takes around 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 that makes a good resting point for 5 minutes. The next hour follows the 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 Akadakekōsen. This hut serves as basecamp for all the routes in the area.
As you exit the Akadakekōsen 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). For this route you need the latter path.
Follow the trail for about 20 minutes through the forest and you will come to a signpost pointing right into the bottom of the Daidoushin runze. Continue along the trail for another 5 minutes and you will reach another junction at the bottom of the Uradoushin runze (runze is Japanese for ‘gully’). If you continue straight along the trail you will soon reach the first waterfall of Jougosawa (ジヨウゴ沢), but for today’s route turn right into the wide lower section of the Uradoushin.
Looking back at the lower slopes:
Hike up the runze, and after about 10-15 minutes the walls will narrow and you will reach the first waterfall (F1). Depending on conditions that year, it could be thin, fat or even almost buried under the snow. F1 is up to 15m, although this year when we climbed it (Jan 2011) the bottom third and the sides were banked out.
After F1 continue up the snow slope past another sawa on your left, to reach F2 (40m), a longer series of steps. Pass another sawa on your left and you will reach F3 (8m). A longer snow slope brings you to F4 (20m), and above this you will see the crux pitch of F5. F5 is only 10m, but unlike the previous falls, it is vertical in its top half. A fairly leisurely pace should see you at F5 within 2-2.5 hours.
Getting over the lip of F5:
Once you have passed F5, you will see that the gully ends in a vertical wall which the ‘Challenge! Alpine Climbing’ guidebook describes as F6. This probably forms only rarely, if ever, and the natural way to finish the route is to traverse right, up the steep slope of frozen turf and rock that skirts under the Daidoushin rock pinnacle (大同心). From here the rock wall of the Daidoushin looks formidable.
Skirting the Daidoushin:
After a traverse of about 100m you will reach a saddle in the Daidoushin-ryo (大同心稜). Looking down from here you have the Uradoushin on your right and the Daidoushin runze on your left. Up above on the other side of Daidoushin runze you will see the Kodoushin rock pinnacle (小同心), with the Kodoushin Crack cleaving it down the front.
At the top of the Daidoushin-ryo descent ridge:
Walk down this ridge for about 45 minutes (be careful with your footing in places) and you will enter the bottom of the Daidoushin runze, from where a further 5-minute walk will bring you back to the main trail.
Depending on time and energy levels, if you want to get something else done, you could take a walk into Jougosawa for some more water ice climbing, or head back to the hut and climb on the ‘ice candy’ artificial ice wall.
The Uradoushin is a fun and straight-forward ice route, which can be combined with Jougosawa or the ‘ice candy’ to provide a fantastic day of ice climbing, and can be done relatively safely even in strong wind or less-than-perfect weather due to the protection offered by the side walls of the gully.