All twelve-tone musical works have 48 tones. According to relevant public information inquiries, it is known that twelve-tone music was developed in Europe in 1908 by Schoenberg, the originator of atonal music. The system of twelve-tone music is negative music. When composing, a unit composed of twelve semitones is called a sound sequence or sound group. It is stipulated that there must be no two identical sounds in a sound group, nor can any one be missing. Twelve-tone sound groups are used flexibly in a free way, so it is also called the twelve-tone system.