Tabsar (Tobsar) was brought onto the permitted list in 2002. On the HGM-Finn map it is clearly marked as Tabsar (6,065m) at 28°34'51.27"N, 85°3'24.90"E in the Chamari Himal. However, coordinates given in the recent Ministry of Tourism list confusingly locate it approximately 5km to the west-northwest of this summit, at Peak 6,057m (28º 35' 41"N, 85º 00' 19"E).
The three previous known attempts on Tabsar appear to be on the peak designated by the HGM-Finn map. The first known attempt was by two Japanese and three Sherpa in the autumn of 2008. Approaching via the Tsum Valley (a.k.a. Shar Khola) and Mu Gompa (monastery), they made base camp at 4,500m, northwest of the mountain. They attempted the north face but abandoned at 5,300m due to crevasses and rockfall, and they determined the north ridge would be too difficult.
An attempt is also recorded in the spring of 2013 by two French climbers, but details are not known. In November 2014, a large, primarily British commercial expedition approached via Mu Gompa with the intention of attempting the south ridge. They established base camp above Mu Gompa at 4,200m but were defeated by an icefall at about 4,800m in the glacier above, which proved too difficult for the clients. In 2015, an attempt by IFMGA guide Tul Singh Gurung was thwarted because of the earthquake, while in 2016 IFMGA guide Sunar Bahadur Gurung failed due to the icefall conditions and bad weather.
In September, IFMGA guide Narendra Shahi (Naren Thakuri), with Iman Gurung and Samir Gurung, trekked one week from Sotikhola to Mu Gompa (ca 3,600m) in the Tsum Valley. The three then climbed around 1,000m up the hillside to the southwest to establish base camp below the glacier that lies southeast of Tabsar.
Leaving early on September 30, the party ascended scree for one and a half hours to reach the glacier, and then climbed this easily for another one and a half hours to reach the icefall. This gave some technical climbing with hidden crevasses. Eventually they reached a flat section at around 5,600m, where they camped. Waking before 3 a.m. on October 1, the climbers left their camp and continued southwest up the glacier, passing below the south ridge of Tabsar, to reach the initially rocky northeast ridge of Peak 6,056m (HGM-Finn), an unnamed top southwest of Tabsar. They climbed this loose terrain, then the snow ridge above, to the summit of Peak 6,056m, which gave a fine panorama of the Ganesh and Langtang himals, including Xixabangma. Their phone GPS recorded 6,110m.
[Editor’s note: Peak 6,056m is one of three unnamed tops to the southwest of Tabsar, rising between it and 6,425m Langu Himal. The other two include an unmarked higher top (ca 6,100m) to the southwest of Peak 6,056m, as well as Peak 6,210m. These three will generally involve snow climbs, while Tabsar is predominately rocky.]
– Lindsay Griffin, with information from Narendra Shahi (Naren Thakuri), Nepal