Yes, and there was involvment in the Civil War too which was great to endear them at the eyes of the Reds . Do you have any idea of Japanese zones of operations at the time so we can make an idea and correlate to possible resource zones? Mind you, these were known rather later, as Siberia was only good for reindeer and furs. Gold, diamonds and oil started to be explored a lot later than the WWI / Civil War timeframe. And Siberia is awfully big, so chances of a Japanese stumbling upon a pot of gold (which exist only in Ireland, as we all know) seems pretty slim.

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