Yatsugatake (八ヶ岳) ice-climbing - The left fork of Hirogawara-sawa (広河原沢左俣)

Route Name: Hirogawara-sawa (広河原沢) left fork (hidari-mata 左俣)

Mountain:  Amidadake (2805m 阿弥陀岳)

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

Time:  1 day round trip

Grade:  WI4 / Overall grade 3 alpine route

While the crowds head to the Akadake-kousen area of west Yatsugatake for early winter ice-climbing, the longer and more varied routes in the Hirogawara-sawa valley provide a much quieter and more immersive experience. The left fork is the longest and most technical of the frozen sawa routes on this side. With several hours of WI2-3 slab ice and a couple of crux pitches at WI4, it is both a first-class training day and a grand outing in itself.

With the option to summit 2805m Amidadake with stunning winter views all around, and then a huge descent down the endless Okoya ridge, expect a tough but satisfying day.

Getting there:

There is no public transport to the trailhead for this route. As a pre-dawn start is required, it is therefore necessary to travel by car.

If travelling by car from Tokyo (東京) take the Chuō Expressway as far as the Kobuchizawa (小淵沢) interchange. After passing through the ETC barriers, turn right and drive uphill on route 11 for around 5 minutes to a set of traffic lights. Turn left and continue until route 11 changes into route 484. Stay on route 484 for around 10 minutes, and then turn right onto a narrow road uphill in the direction of Funayama-jūjiro (船山十字路). There is space for around 15-20 cars to park here.

Description:

From the carpark at Funayama-jūjiro walk up the road for several minutes and pass through the gate. Continue up the forestry road in the direction of Hirogawara-sawa. Eventually the road becomes less defined as it narrows into a valley path.

After about an hour of hiking the path crosses to the right bank of Hirogawara-sawa. Another 20 minutes will bring you to the Futamata junction (二俣), the point where the left and right forks of the river part ways.

Cross back over to the left bank and then continue hiking up the left fork. The angle increases slightly as you pick your way up the snow-filled streambed, and gradually you will meet more and more frozen sections and short 1-2m steps. After around half an hour you should reach a pool with a narrow cleft at the far end. This is the start of the more technical climbing. Some years this is frozen and you can go straight up it, but if it is still running water here, it can be bypassed up on the cliff on the left side, with a fixed rope at the far end to get back down into the streambed.

Now you are into the more technical ice-climbing, and as you progress up the sawa you will meet several ice steps of around WI2-3 up to about 15m in height. They can all be soloed in good conditions if you have the confidence, but be prepared to pitch them if necessary.

As you gain height you will eventually come to the mixed crux of the route, involving a traverse across a steep slope followed by a climb up a bulging chimney in two sections. If you want to rope up for this, there is a good tree anchor at the top.

After some more slab ice and one slightly longer 3-step icefall, you will come to the first of the ice cruxes, the 15m WI4 Ōtaki icefall (大滝). This pitch is off vertical for its first half, but then steepens to vertical in its upper half, with a solid tree to belay from at the top.

Once over the Ōtaki, continue up the sawa and climb several more WI3 sections of steep exposed slab ice.

Eventually you will reach the technical ice crux of the route, the final WI4/4+ ice pillar. Conditions on this pillar differ year to year, and it can be fat solid ice or rather intimidating, but it usually touches down on the ground and can be climbed by mid to late December. There is a solid anchor some metres back from the top.

Ice pillar in different years:

You have now finished the technical ice-climbing, and have a couple of options available. If you want to go to the summit of Amidadake, continue up the sawa on more moderate terrain until you break out onto the upper slopes and hit the hiking trail near the top. If you are not planning to go to the summit, then just climb the steep slopes on your left until you hit the hiking trail on the Okoya ridge (御小屋尾根), effectively the west ridge of Amidadake.

Descent:

There is usually a great trace all the way down the Okoya ridge. Pick your way carefully down it, and after around an hour you’ll come to a sign for a water source off to the left (不動清水) at about 2206m. Keep going down the ridge and after another 1h10mins of map-time you will arrive at a fork in the trail just after the 2137m summit of Mt Okoya (御小屋山).

The right fork goes to Minotoguchi bus stop, and the left fork will take you back to Funayama crossroads. The car park at Funayama crossroads is another 1h20mins of map-time down the ridge.

Overall:

A classic winter ice/mixed alpine route in the Yatsugatake region, favoured for its length and sequence of frozen waterfalls and ice pitches up to WI4. Take a 50m rope and around 8 ice screws, and be prepared for a big day out.