The development history of the staff. ★In the 9th century AD, the "Num" notation appeared, a notation method that uses "dots", "hooks" and "strokes" to mark sounds. First, there is a line indicating the position of the f sound, and the other sounds are above and below f. Later, a C line was added to establish the approximate position of the note. ★In the 11th century AD, "Guido d'Alezzo" added four lines, and the range was about an octave, making the recording of sounds more accurate. "Guido d'Alezzo" has since been hailed as the father of the staff. ★Later, due to the needs of duet singing and performance, six-line, seven-line notation, and even eleven-line notation were gradually produced. ★In the 16th century AD, all countries in Europe unified and changed the complicated situation caused by too many horizontal lines, and used additional lines to express sounds that were too high or too low. ★Later, there were treble, alto and bass clefs, large clefs and full clefs for recording scores of various musical instruments. ★Stave notation has become a common notation method in all countries in the world today.