Scratching, sometimes referred to as scrubbing, is a DJ and turntablist technique used to produce distinctive percussive or rhythmic sounds and sound effects by moving a vinyl record back and forth on a turntable while optionally manipulating the crossfader on a DJ mixer. While scratching is most commonly associated with African-American hip hop music, where it emerged in the mid-1970s, it has been used in the 1990s and 2000s in some styles of pop and in nu metal. Within hip hop culture, scratching is one of the measures of a DJ's skills. DJs compete in scratching competitions at the DMC World DJ Championship and IDA (International DJ Association, formerly known as ITF (International turntablist Federation). At scratching competitions, DJs can use only scratch-oriented gear (turntables, DJ