Start with musical notation, including key signatures, time signatures, and rhythmic symbols.

The three related uses of "music theory" are: the first is "basic principles", which is the music symbols that must be understood, including key signatures, time signatures, rhythm symbols, etc. The second is to learn from ancient times Scholars have studied music so far. The third is a subfield of current musicology research that aims to "seek to define the procedures and universal norms of music." It is different from music analysis and does not focus on individual works and performances. The basic rules that constitute music.

The sum of sounds with fixed pitches used in music is called a musical tone system. The sounds in the musical tone system are arranged in ascending or descending order, called a tone sequence. Each tone in the musical sound system is called a sound level. There are two types of sound levels: basic sound levels and modified sound levels. In the musical sound system, the seven sound levels with independent names are called basic sound levels. It is marked in two ways. Two adjacent notes with the same name are called octaves. The sound obtained by raising or lowering the basic pitch level is called a change of pitch level. " or "#" to indicate; lowering a semitone to indicate "flat" or "b"; raising a whole tone to indicate "re-rising" or "※"; lowering a whole tone to indicate "re-falling" or "bb"; Reduction is represented by "n"