On August 15, Antonin Borovka, Lukas Kroker, Jaroslav Musil, Josef Smrtka, and I, all Czech, arrived at the village of Patkhor. We set off for the Shteklozar Glacier, which is hard to reach, as in the upper parts of valley there is no path and one has to cross large boulder fields. It took us three days to cover the 22km to our base camp at 4,350m in the eastern branch of the Shteklozar Valley, near the glacier.

After a reconnaissance, we decided to attempt an unclimbed peak northeast of Klunnikova Peak (5,422m) in the Patkhor group. On August 19, in one long day’s climb from base camp, we ascended the western side of the glacier, through two steps of an icefall into the upper cirque between Patkhor (6,083m) and Klunnikova (5,422m), then turned west to our unclimbed peak (37.8713911N, 72.1754588E), which we called Rushan Castle (Rushanykiy Zamok in Russian; Kalai Rushon in Tajik), estimated to be 5,375m. The final ascent led over a crevassed glacier to the summit, comprised of a long, unstable cornice. Only Kroker and Smrtka climbed to the very highest point; the rest of us stopped and belayed just below the cornice. [Rushan Castle is a subpeak on the northeast ridge of Klunnikova, which is just south of Klunnikova Pass. Klunnikova was first climbed in 1946 and has been climbed multiple times from the pass; the 2023 route climbed more directly up the northeast ridge.]

— Michal Kleslo, Czech Republic