I happen to purchase this interesting coin. From my understanding of this, this coin was to commemorate promulgation of the provincial constitution on 1st Jan 1922. More information can be found here: http://ykleungn.tripod.com/hunanty.htm While it's not rare, it's not very common. It originally had more grit on it which I successfully have removed and it's showing it's nice condition. Initially I thought I would be handling this coin full of verdigris but thankfully this wasn't the case. I've also managed to get hold of the 10 cash version but that went straight to preservation due to severe corrosion. Still, quite neat for a coin that doesn't appear in the market very often.
There are two versions of this 20 cash coin. The more common version has the date as "January 1" (一月一日) as on your coin. The much rarer version has the date as "January" (一月). The two versions can be seen at this Chinese website. The first coin is the rare "January" specimen. The second coin is your "January 1" version. Incidentally, there are also several versions of the 10 cash coin. You might want to compare your 10 cash coin with the various versions displayed at this website. Gary
