Got the two of these for one dollar total today. They aren't in the best shape, but it's from an interesting and troubled period of China's history. I believe they are: L 50 Customs Gold Units, 1930; R 10 Yuan 1937
I don't have any special insights into the history. My family has Northeast Asian heritage on my wife's side (Chinese/Manchu/Mongol and maybe some Korean). I personally knew relatives of hers who had lived through the Warlord Era, Japanese occupation, and Civil War with the Communists. So I find coins and bills from that time of special interest. It's not paper money, but here's some occupation coinage. Manchukuo 1934 5 fen copy 10 Fen Hua Hsing Bank 1940 Various occupation money
I also find Chinese paper money fascinating. I don't have any as old as the ones posted above, but I've picked up a few along the way. Here are some samples:
