Google’s Ngram Viewer makes interesting book research possible.
I came across a book called The Japs at Home from 1894. I was surprised “Japs” was in use that far back. I thought the slur was created for World War II propaganda purposes.
That got me wondering about racial slurs in books and this chart is just shocking. I entered four well-know racial slurs: Nigger, Jap, Coon, Chink.
Nothing comes even close to the slur used against Africans.