This page uses content from Wikipedia and is licensed under CC BY-SA.
The earliest recorded occurrence of the slur seems to be in the Time magazine of 5 January 1942 where "three Nip pilots" was mentioned. The American, British, and Australian entry of the Pacific Ocean theatre of World War II heightened the use of racial slurs against the Japanese, such as Jap and Nip. The word Nip became a frequently-used slang word amongst the British Armed Forces. The 1942 Royal Air Force journal made numerous references to the Japanese as Nips, even making puns such as "there's a nip in the air" This phrase was later re-used for Hirohito's visit to the UK in 1971 by the satirical magazine Private Eye.
As part of American wartime propaganda, caricatures and slurs (including Nip) against the Japanese diffused into entertainment, such as exemplified by the Warner Bros.' cartoon Bugs Bunny Nips the Nips (1944). In General Kenney Reports: A Personal History of the Pacific War (1949), George Kenney made racial statements about the Japanese, remarking for example that "Nips are just vermin to be exterminated".
In a manner to evoke further anti-Japanese agitation, a Seattle Star editorial titled "It's Time to do Some Thinking On Nips' Return" from December 14th, 1944 discussed the citizenship rights of Japanese-Americans and framed their return to American society as a problem.