Battle of Warsaw (1920)
The battle of Warsaw was fought from August 12–25, 1920 as Red Army forces commanded by Mikhail Tukhachevsky approached the Polish capital of Warsaw and the nearby Modlin Fortress. On August 16, Polish forces commanded by Józef Piłsudski counterattacked from the south, disrupting the enemy's offensive, forcing the Russian forces into a disorganized withdrawal eastward and behind the Neman River. Estimated Russian losses were 10,000 killed, 500 missing, 30,000 wounded, and 66,000 taken prisoner, compared with Polish losses of some 4,500 killed, 10,000 missing, and 22,000 wounded.
Biuro Szyfrów
Polish cryptologists enjoyed generous support under the command of Col. Tadeusz Schaetzel, chief of the Polish General Staff's Section II (Intelligence). They worked at Warsaw's radio station "WAR", one of two Polish long-range radio transmitters at the time. The Polish cryptologists' work led, among many other things, to discovery of a large gap on the Red Army's left flank, which enabled Poland's Marshal Józef Piłsudski to drive a war-winning wedge into that gap during the August 1920 Battle of Warsaw.