The fan-shaped rolling of the fingers on a certain position on the string is called "rubbing the string". The rubbing of the string will make a wave-like sound. The proper use of the rubbing string can make the melody more singing and enrich the playing skills of the erhu. If changing the handle is the first door to improving the expressiveness of the erhu, then the vibrato is the second door. Vibrato marks the player's foundation, musical literacy and playing style. If a player cannot use vibrato, it means that his playing skills are still at an elementary level. Once you are proficient in vibrato, mastering fingering skills such as percussion and vibrato is easy and convenient.

Vibration methods can be roughly divided into two categories: fast kneading and slow kneading.

1. Knead quickly

Quick kneading is also known as "flickering fingers", which probably refers to the constant vibration of the fingers when kneading the strings. The specific method is: when a finger of the left hand is pressed on the string, the wrist is dominated by the forearm, making a regular continuous inflection (not shaking) movement, and the finger is also affected by the chain action of the wrist. Vibrate at a steady pace. The elastic vibration of the fingers makes the tension of the strings change accordingly, resulting in a wave of sonic vibrations. Fast kneading is easier to master than slow kneading, but the sound effect is not as pleasant as slow kneading, and its use is not as common as slow kneading.

2. Slowly knead

Slow kneading is also known as "chanting", and the sound it makes is like chanting and chanting. The method of slow kneading is as follows: one hand of the left hand is placed on the string, and the wrist joint is used as the axis to make the entire palm make continuous and regular arc fanning. The speed of fanning is not as fast as that of fast kneading, but the amplitude is larger than that of fast kneading. In this way, driven by the wrist, the finger pressing the string undergoes a reciprocating change, which drives the finger pad to make a symmetrical arc flip within a small range between the up and down of the pressing sound. This not only changes the tension of the strings, but also changes the length of the strings, resulting in a soft and slow singing sound wave, which is a kind of vibrato with the most training value.

The folk performance method also derives techniques such as "kneading, sliding, pulling, pressing" from the slow kneading method. These changes are mainly in the intensity of the string, the speed of shaking, the width of the sliding string, the speed of the frequency and the The difference between the corresponding bow force and quick fit.

Players with certain attainments are very particular about the transformation of vibrato. In addition to the above-mentioned "kneading, slipping, digging, pressing" can be used accurately, you can also knead first and then no kneading, first no kneading then kneading, diffuse kneading and fast kneading, fast kneading and fast kneading, sliding while kneading, or When encountering notes of equal pitch and duration in a melody, some are rubbed and some are not. On the one hand, it depends on the player's solid basic skills, on the other hand, it depends on the player's understanding of the content of the music and mastery of the tune style. The proper use of vibrato in the content and style of the root disturbance music is an essential skill for the performer.