According to V.I. Molotov, on a speech given Oct. 31, 1939, the USSR had 734 KIA and 1862 WIA in their occupation of Eastern Poland. They also captured large quantities of Polish equipment.
Since the Soviet invasion of Eastern Poland is treated as a "special case", I think event 2604 (Eastern Poland to USSR) should cost the USSR an MP point or two, and net them some supplies (perhaps 500-1000?)
Since the Soviet invasion of Eastern Poland is treated as a "special case", I think event 2604 (Eastern Poland to USSR) should cost the USSR an MP point or two, and net them some supplies (perhaps 500-1000?)