... especially those from WWII: Milton Caniff's How to Spot a Jap

Some quotes:

The Chinese has a smooth face .. the Jap runs to hair. Look at theirprofiles ant teeth. C usually has evenly set choppers -- J has buck teeth ... the Chinese smiles easily -- the Jap usually expects to be shot .. and is very unhappy about the wholething ... especially if he is an officer!

...

If you just slap a Jap's clothing to locate concealed weapons you may lose a prisoner -- and your life ... don't unscrew fountain pens or tinker with any object that could contain acid or an explosive. Watch out for sleeve guns and other comic strip gadgets ... The Japs are experts at such stuff ...

See also: Bugs Bunny Nips the Nips, and Tokio Jokio via BoingBoing