What kind of calligraphy is this?

This is an ancient piano score, also known as subtraction score, or notation score or gesture score. It evolved from a written music score, which is said to have been invented by Cao Rou in the late Tang Dynasty. Subtraction spectrum is generally divided into four parts, the upper part records the left-handed fingering, the lower part records the right-handed fingering, the upper left is the left-handed fingering, the upper right is the embossed emblem, the lower part is the right-handed fingering, and the inner part is the plucked string. In addition, there are continuations and notes in the subtractive spectrum, which are generally used to represent subtle changes in sound.