Markel De La Fuente, Oier De La Fuente, Josu Linaza, and I planned an expedition to the Sosbun Valley similar to my 2023 trip to Ladakh (AAJ 2024), where we had a base camp close to a variety of rock walls. We opted to visit the South Sosbun Glacier after seeing photos from a past expedition sent by our friend Asghar from Skardu.

The weather was not ideal: There were rain showers and light (occasionally not so light) snowfall on each day. We reconnoitered the area and dismissed Sosbun Brakk (6,413m) and Sokha Brakk (5,956m), as they seemed full of objective danger. Instead, we selected one of the Sosbun Spires, which looked “safe,” with little evidence of rockfall, and had good-looking rock with a multitude of cracks and corners.

Soft snow, crevasses, and difficult moraine meant it took us 4.5 hours to reach the foot of the wall. We ferried gear to this point and established a camp (4,600m). It appeared there would be a good ledge for a second camp about 400m above. We would fix ropes to that point, then try to complete the route in one day. However, we had to wait through more than a week of bad weather before we received a favorable forecast.

Back at the spire, we all climbed, fixed ropes, and hauled the necessary gear to the proposed camp at the top of pitch seven. The rock was quite good, and although the cracks were sometimes blind, there was no vegetation. While climbing the first two pitches, we spotted three ancient bolts about 50m to our left, but then nothing more.

On what we hoped would be our final push, all four of us spent the night on the ledge and set off the following morning. At 8 a.m., while we were trying to place a bolted belay, the drill stopped working. The rock on our route had not always offered good natural protection, so we thought the most sensible thing was to descend and return with our backup drill. [In addition to bolts at anchors, more than 25 protection bolts were placed on the route.]

Two days later, Markel and I completed the approach up the glacier and by 1 p.m. had climbed the ropes to our camp. (Josu and Oier had opted to attempt a peak from the North Sosbun Glacier but were eventually unsuccessful.) The day was still young and the weather was good, so Markel and I decided to push on to a higher camp. This would have to be our final attempt, as the porters were due to arrive the next day.

We awoke early at our upper camp, on a ledge at the top of pitch 12, at 4 a.m., and soon began climbing. The rock quality was worse than the previous day, and we had to climb through difficult and sparsely protected slabs, wet from melting snow above. After a mixed section, we reached a small shoulder below the final wall. We’d hoped to climb a corner on the southwest face, but it was obviously too wet, so we were forced to climb to the right. There, the excellent granite was interrupted by two overhanging schist bands. On the second band, a small edge broke under my foot and I almost fell. This penultimate pitch proved to be the crux of our route. Pitch 20, a poorly protected thin slab finishing with a nice crack, then took us to the sharp summit.

With continuous rockfall in the couloirs on either side of the pillar, reversing our route was the most sensible option. We needed to make many diagonal rappels, but by 8 p.m. we were back at our top camp.

We named our route Izar Gorri, Mamuon Betiko Argi (800m, 1,140m of climbing in 20 pitches, 7b M4). These central spires of the Sosbun group have been known as Sosbun IV, III, and II, and we climbed Sosbun III. However, the porters referred to our spire as the central of three Mun Brakks (“cut peaks”), and we adopted that name: Mun Brakk II (5,430m, 35°55’7.68”N, 75°30’40.73”E). 

       —Ekaitz Maiz, Basque Country

Historical Notes on the Sosbun Peaks: The upper Sosbun Valley has a long but intermittent climbing history. Doug Scott (U.K.) planned to attempt Sosbun Brakk in 1974 but never got there due to porter problems. This imposing summit was attempted by Germans in 1976 and finally climbed in 1981 by a Japanese expedition via the southwest ridge.

In 1986, a small Polish team led by Janusz Skorek reconnoitered the Sosbun Spires, which run south-southwest along the ridge from Sokha Brakk, and attempted the southeast face of the highest, Spire I (ca 5,500m), from the South Sosbun Glacier.

In 1988, a strong Austrian team led by Robert Renzler tried to climb the massive east face of Sosbun Tower (ca 6,000m) but were foiled by bad weather. (More than six meters of snow fell at base camp during their time in the area.) Instead, they returned down-valley and made the first ascent of Hikmul (6,300m+) via the Hikmul La to the north.

That same year, Italians Daniele Bosisio, Adriano Carnati, Tita Gianola, and Paolo Vitali completed the first ascent of Sosbun Spire I, climbing a route left of the Polish attempt (800m, VI+ A1, 350m of rope fixed).

In 1989, a French team led by Bernard Domenech tried the impressive east face of Sosbun Tower. They climbed 700m up this 1,100m face, found the rock appalling, and eventually gave up, having overcome difficulties of 6b A4. In 1999, Yasushi Yamanoi’s party also attempted the east face of the Tower, but they too gave up in the face of awful rockfall. This Japanese team then climbed the northwest face of an unnamed peak between Sosbun Brakk and Pamshe (60° snow, followed by a few pitches of V A2) on the Sosbun-Biafo divide.

In 2011, an all-female Polish team climbed some small summits toward the (southern) end of this same ridge and a rock tower near base camp. See report here.