Allegro is a traditional percussion instrument in China, also known as Allegro, which consists of two long bamboo boards. When playing, one hand holds the board and the other hand hits it with a bamboo stick. There are many ways to play Allegro, among which "knotting" is a common playing skill.

In Allegro performance, "double-point drilling" is a skill, which refers to hitting the two sides of Allegro alternately with two bamboo sticks. As for the placement of thumbs, different players may have different habits, but there are usually the following ways:

1. Put your thumb on the "ox nose button" (the small hole or decorative part at the top of Allegro) a little higher, which can better control the stability and hitting strength of Allegro.

2. Lower part of the bull's nose button: Some players may be used to putting their thumbs on the lower part of the bull's nose button, which makes it easier to make quick strokes.

3. Adjustment according to comfort: The specific placement position of thumb should be adjusted according to personal comfort and playing habits. It is important to keep your hands relaxed and flexible so that you can play smoothly.

4. Skill requirements: The stability of thumb is very important in "double-point drilling" to ensure that Allegro will not slide or turn over in your hand.

5. Practice and experience: With the accumulation of practice and experience, the performer will find the most suitable way to hold the board.

Each style of play and placement has its own characteristics and applicable occasions. It is suggested that through practice, observe the skills of different players and find the best way to play. If you have the opportunity, you can learn from experienced allegro players or refer to teaching videos to improve your playing skills.