[dhathorn]

It's a chinese flag, the old republic of china flag. Also known as the five races flag.

https://en.wikipedia.org/wiki/Five_Races_Under_One_Union

[mxuribe]

Ah-ha, weird, after immediately seeing the flag, I went to Wikipedia...but on the Chinese flags page they didn't list the flag that you found...which does answer the mystery for me! Thanks!

[rolltiide]

It's like a precursor to the "one country two systems" moniker, which is really one country five systems if you actually count.