The Shim Dur (a.k.a. Shahim-i-Dur) Valley lies in the little-known Insgaiti or Wesm Mountains, which lie between the Braldu and the Shaksgam rivers. The main peak of this subrange is the Crown (7,295m).

In September 2017, Agnieszka Garus-Saramak, Andrzej Makaran, Justyna Markiewicz, and Mariusz Saramak (Poland) traveled by vehicle from Kasghar in China, via the Khunjerab Pass and Sost, to Shimshal, then trekked over Shimshal Pass to the Braldu. They eventually established base camp at 4,520m below the snout of the Shim Dur Glacier.

By the 24th they were all camped at 5,260m in a side glacier northeast of the Shim Dur. On the 27th, all four climbed snow slopes up to 45° to reach the summit of the peak at the head of this side glacier, which they named Okheree Sar (6,119m on the China-Pakistan border map; 6,132m indicated by two altimeters; 36°18'22.86"N, 75°57'19.34"E). The excellent panorama included the highest summit above the Shim Dur Glacier, which they named Shim Dur Sar (6,495m).

The party confirmed that the best time for mountaineers to visit this area is late September and October. Conditions were relatively good; there were only three nights and one day of minor snowfall during their stay. They felt the general area was safe, and local people treated visitors very kindly.

– Jerzy Wala, translated by Monika Hartman and Janusz Majer, Poland