21st Uhlans with Saxon Cavalry Sabers

Very nice hard to find Degan Bob. EXCELLENT photo and here is why:

The Sachsen Ulanen had a peculiar habit after 1910 of wearing numbered straps on the Dunkelblau Ulanka in lieu of epaulettes for the three Sachsen Ulanen Regts. Photographs of this pattern show that only numbers were worn, never the regimental cypher, and the straps were sewn into the shoulder seams and were not removable.

Here is a scarce example of this unusual Ulanka pattern worn by Ulanen Regt Nr. 21. Instead of scaled brass epaulettes with a cypher, he wears cloth straps of the same blue material as the Ulanka, piped in white with a white #17. Better yet, most in your photo have slip-on straps, possibly greatcoat?