It is from the Polish-Russian war of 1919-1920, which was then called the "Polish front" by the Bolsheviks. The tell is that there is РКП (Russian Communist par

It is from the Polish-Russian war of 1919-1920, which was then called the "Polish front" by the Bolsheviks. The tell is that there is РКП (Russian Communist party, which was the name used for a short period before the founding of the USSR in 1922 when it became КПСС)