The more I think about it, I am pretty sure that is an American flag flying from that flagpole. There are several more pics of the game around here somewhere but it would take me weeks to find them.
I can’t imagine an American flag if that was in the Russian sector.
Still, I hope you check with them. It might be interesting to see if they know any more about the game.
You never know. Things were pretty fluid in 1945.
Sent them the email. I’ll FReepmail you if I hear back.