The Czechoslovak Legion, formed initially of Czechs and Slovaks resident in Russia, fought on the Entente side in World War One.  When the Bolsheviks started negotiations with the Central Powers, the Legion aimed to leave for the Western Front.  This was permitted, but only via Vladivostok on the Pacific Ocean, across the breadth of Russia.  By May 1918, Czechoslovak legionaries had reached Cheliabinsk (Celjabinsk in the upper map (middle, highlighted in green)).  There, the uneasy truce between the Legion and the Bolsheviks collapsed when a man was killed in a fight.  Trotsky subsequently issued an order to disarm all legionaries and kill those who resisted.

The maps here come from the memoirs of one of the Legion’s commanders, Radola Gajda.  The red flags show major Russian forces and the green squares denote the locations of Legion divisions.  Both maps depict the state of play on 25 May 1918, with the upper showing the Urals and the lower showing southern Siberia.

Moje paměti / Radola Gajda (1921)  S586.a.92.4