They can't tell us apart
Thanks, Julian for the following slice of history.
Back in late 1941, Japan bombed Pearl Harbor and America was pretty much hating on anyone looking remotely Asian. To ensure the venom was flowing towards the right peoples, Life Magazine published some pictures and diagrams (complete with ESPN style chalkovers) addressing what they identified as the "distressing ignorance on the delicate question of how to tell a Chinese from a Jap."
See the article and diagrams here.