The sum of notes with fixed pitch used in music is called music system. The tones in the musical system are arranged in ascending or descending order, which is called a tone train.

On the piano, you can clearly see the notes and sequences used in the musical system. At present, the largest piano includes 88 notes with different pitches. Other sounds are almost useless in music.

each tone in the musical tone system is called a scale. There are two kinds of sound levels: basic sound level and changing sound level. In the musical system, seven levels with independent names are called basic levels. The sound produced by the white keys on the piano is consistent with the basic sound level.

the names of basic tones are marked by letters and roll calls. Fifty-two white keys on the piano repeatedly use seven basic tone names. Two adjacent sounds with the same name are called octaves.

the tone obtained by raising or lowering the basic tone level is called the changing tone level. Raise the basic sound level by a semitone and mark it with "L" or "#"; Decreasing semitone is marked by "drop" or "b"; The rising whole tone is marked by "re-rising" or "x"; Lowering the whole tone is marked by "falling again" or "bb".

in the german system, suffix is used to indicate the changing sound levels: is (ascending), es (descending), isis (ascending) and eses (descending).

but e-drop uses es instead of Ees; Use as instead of Aes to drop a; Use b instead of hes in h-drop.