Doppa
An Uzbek man wearing a doppa
The Doppa (Uyghur: دوپپا, ULY: Doppa), a square or round skullcap originating in the Caucasus and worn by Kazan Tatars, Uzbeks, Tajiks and Uyghurs. The Doppa means hat in Uyghur but however a baseball hat is not called a "Doppa" normally. The doppa is derived from a Turkic, more pointed, ancestral cap, which can be seen in some of the portraits of Jalaleddin Mingburnu.
The Sunday closest to May 5 every year is now widely accepted as the Doppa Bayramı (The Uyghur Cap Festival) in China and in all countries with Uyghur communities.