Please do not use the term "jap" because the word is pejorative. Many people who use the term do not realize ALL Japanese Americans find the word offensive. One does not say "nigger folk songs" or "kike melodies" or "spic songs" or "chink music."
The sensitivity to this word occurs because there was a time not long ago in this country when Japanese Americans were evicted from their homes and locked up behind barbed wire fences with machines guns guarding the entrances. The year was 1942. The event climaxed more than a half century of anti-Asian prejudice. No doubt imperialist Japan was a cruel, despotic dictatorship. Japanese Americans were lumped into the same category as the people perpetrating brutalities on Asia, but the Japanese Americans were patriotic and loyal Americans. Nonetheless, the disparaging moniker "jap" was applied to anyone who had such ancestry.
Culturally, Japanese Americans usually have been taught to keep quiet and often do not speak up when offended. But believe me, as a Japanese American, the term is offensive, so, please, kindly refrain from the use of the term.
The Japanese American Citizens League has protested without complete success to Ebay and other sites which use the word "jap" in such a casual manner. The preferred abbreviation, by the way, is "jpn." I would hazard a guess the majority of the people who say "jap" are totally unaware of the heavy overtones of racial hatred the word has carried in the past. Thank you for your forbearance in hearing me out, but it was important for me to say since I highly regard this site and its members.