On the Legal System in Music

Commonly used are the law of twelve averages, the law of five degrees and the law of purity. The law of twelve averages is to divide the six whole tones in CDEFGAB into 12 equal semitones. The pentatonic scale law is a scale that starts with the C tone and extends from five degrees up to five degrees down. Let me give you an example: the fifth degree of C is G, and the fifth degree of C is F, so the relationship between the fifth degree of G and the fifth degree of F is pentatonic. Pure law consists of seven octaves like chords. The three laws have their own advantages in practical application. Five-degree law is suitable for single-part music, pure law is suitable for multi-part music, and twelve-average law is basically adopted because of its convenient modulation.