"I think the film clip foolestroupe is referring to is of soldiers of the soviet red army celebrating their conquest of Berlin."

No - this was not russians - it was used during some pre-war German scenes - german clothing etc. (and I DO know that doco makers use film clips that are not always 'kosher')

The Chinese supposedly did invent the free reed instrument - but they did NOT invent the concertina/accordion as used in the West. There may well now be more accordion player in china most other single countries nowadays.