Continuing the Czarist tradition, this is a BIG coin. That's the reason it's so difficult to find: copper prices tend to rise extremely quickly in war time. Even in the rich, faraway United States, copper pennies were temporarily struck in brass and in the occupied European countries, copper issues stopped altogether.
IMHO this is also one of the best designed and executed coins under communism, struck at a time that Winston Churchill made complimentary remarks about Stalin in his diary.
Peter