Key signature in notation refers to the way in which different pitches in music are represented by numbers. Usually, the numbers 1 to 7 are used to represent the notes in music, 1 represents the first note of a scale, and so on. Key signature is used to indicate the basic pitch and tone used in songs. For example, C major is the tonality with C as the basic pitch. Therefore, when reading the notation, we can understand the tonality of the song through key signature, so as to better understand its music structure and melody.

Understanding key signature's symbols helps us to play and rehearse music works better. By memorizing key signature, we can distinguish different pitches faster and better grasp the harmony and rhythm of the tracks. In addition, if you know the tonality of songs, you can better arrange and organize chorus or instrumental ensemble tracks to ensure that all players play in the same tonality and style.

Key signature with simple notation often appears in various music examinations, which is especially important for students and music lovers. Each grade involves various tonality, which requires the player to master the corresponding key signature and pitch skillfully. Therefore, mastering key signature's notation is not only helpful for us to appreciate and play music, but also one of the necessary knowledge for learning music.