From April 27 to May 3, Alexander Gukov and Alexey Lonchinskiy from St. Petersburg, Russia, made the coveted first ascent of the southwest face of Thamserku (6,618m).

Despite being an obvious target, within easy distance of Monjo (much of the southwest face is seen by Everest trekkers during their ascent to Namche Bazaar), there had been only one known previous attempt. In October 1986 the four-man Spanish team of Jose Manuel Gonzales, Jose Luis Fernandez, Azucana Lopez, and Miguel Rodriguez first climbed to a bivouac at 5,700m in the prominent central couloir. The next day they continued through a difficult rock barrier (65°–90°) to a second bivouac in an ice cave at 5,900m. On the third day they reached 6,300m, where they used hammocks to bivouac. By now they were experiencing significant problems with their stoves, and next morning they found the gas had leaked and there was no way they could melt snow. Reluctantly, they abandoned the climb a little over 300m below the top.

Before their attempt, the two Russians ascended the Kyashar Khola from Monjo toward base camp for the normal route on Kusum Kanguru. Camping in the main valley at ca 4,100m, they made an acclimatization attempt on Point 5,572m, which lies on the northwest ridge of Kusum Kanguru. They failed, descended to Monjo, and then traveled to Island Peak, which they summited, camping for the night at 6,000m.

Returning to Monjo, they headed once more along the Kyashar Khola before striking up the hillside to the left, toward the southwest face of Thamserku. There were no paths; they kept right of a long spur, wading through dense bush and over grassy talus. With heavy packs it took them two full days to reach a pleasant base camp at 4,850m.

From there they set off in alpine style, carrying a small tent without poles that they could use as a sort of hammock where there was nowhere big enough to cut a tent platform. The pair took the objectively safer central spur, immediately left of the couloir attempted by the Spanish. Gukov and Lonchinskiy made six bivouacs before reaching the summit, finding the climbing to be mainly snow, ice, and mixed, with an average steepness of around 70°. There were many sections of M4–M5, and four pitches of A2: two right at the start, and two in the steep, rocky middle part of the spur, immediately above the second bivouac. The second pitch after this bivy was probably the crux (and was exposed to spindrift), and the following pitch also was difficult, stretching to 80m because of the impossibility of arranging a belay earlier. Bivouacs were sited at 5,325m, 5,600m, 5,780m, 6,100m, 6,350m, and 6,570m.

From the top they descended the south ridge for seven rope lengths, bivouacking for a seventh time at 6,300m, before making 22 rappels down the southwest face to the glacier.

They measured the height of the face as 1,623m, and estimate a total climbing distance of 1,900m to the summit. They have named the route Shy Girl, and consider the overall grade to be Russian 6A/6B.

To date there have only been six confirmed ascents of Thamserku, four of these from the south. The peak was first climbed in 1964 by members of Edmund Hillary's Himalayan Schoolhouse expedition. Lynn Crawford, Pete Farrell, John McKinnon, and Richard Stewart approached the south ridge from the basin below the southwest face, climbed a difficult couloir onto the crest, and then followed it a long distance to the summit. They found the climbing to be exceptionally difficult—much like a technical ascent in the Andes, with steep flutings, mushrooms, and cornices. Four camps, 1,200m of fixed rope, and 30m of rope ladder were used. The route has never been repeated in its entirety, though the Korean team that made the fourth ascent of the peak in 1984 reached the south ridge from the east.

In 1979 a Japanese team climbed a spur left of the main southwest face to reach the crest of the west ridge at a col right of the prominent 6,341m top on the crest. Just below this point they made their last camp, at 6,300m. From there Sakai Hosogai and Satoshi Kimura set out for the summit and found difficult climbing to get to the rocky foresummit at ca 6,600m. Here they were forced to bivouac before continuing to the main top next day.

Lindsay Griffin, from information provided by Anna Piunova, Mountain.ru