I've been noticing on high denomination bills recently that there are a lot of strange symbols marked by someone. The pic below shows some from $100's I received from Las Vegas casinos recently. Most seem to be some kind of asian symbols.... japanese, korean, chinese??

I'm wondering if these serve the same purpose as the 'chops' that far-east merchants used to stamp on US silver dollars when they accepted them in payment. Their unique mark would indicate they were satisfied they had full silver content and would be accepted as payment in future trades. These chops were also frequently found on US Trade Dollars that were specifically made in the 1800's for foreign trade.

I've never seen any discussion of their use on US currency but since the big majority of US $100's reside outside the country, this could be another way to indicate the bill was proven genuine to someone.

Any ideas? There must be a few cross collectible hobbiests out there who collect paper currency... or maybe someone who works in a bank?

DonL