Bar lines are used to divide obvious sections of musical works. Two identical bar lines used to indicate the end of a piece of music are called double vertical lines, also called compound vertical lines.

In music scores, in front of the downbeat, the vertical lines used to divide the beat units are called bar lines. The two bar lines used to indicate the end of the whole song, the right one is slightly thicker than the left one, are called the termination line.

Bar line music always alternates between strong beats and weak beats. This alternation cannot be chaotic or arbitrarily arranged, but should be organized into a small section according to certain rules to form the smallest beat, and then use this as a basis. The cycle goes back and forth.

For example, when there is only one weak beat between two strong beats, it is called "two beats", and 2/4 beats are of this type; when there are two weak beats between two strong beats, It is called "triple beat", like ¾ and 3/8; there are three weak beats between the two strong beats, which is called "four beat", the common one is 4/4.

The bar line is a thin line perpendicular to the staff, with five lines on top and one line on the bottom, which just cuts off the staff. No matter how far away the upper and lower lines are from the staff, the bar line cannot Beyond the staff.

Features of music notation

Music notation is a method of recording music using symbols, produced by printing or handwriting. Different cultures and regions developed different notation methods. Notation can be divided into two categories: recording pitch and recording fingering. Staff notation, simplified notation and Braille notation are all musical notations that record pitches. The guitar's six-line notation and the guqin's subtraction notation are both musical notations that record fingerings.

In ancient China, there were the five tones of Gong, Shang, Jiao, Zheng, and Yu, which corresponded to the Western roll names Do, Re, Mi, Sol, and La. They were the basic notes of music scores. When composing ancient music, they were based on One of them sets the tone, and the length of the syllables, quarter notes, and notes is only reflected in the music.