Hulusi duplication is to use one or several tones to play a decorative role. This technique is relatively common. Duplication is played mainly through the agile movements of fingers, and the sound hole and adjacent or spaced sound holes are pressed quickly and accurately.

In the use of duplication, a very short decorative tone is usually added at the beginning of the phrase and between two melodies of the same degree. It is similar to appoggiance, but has no obvious appoggiance effect. Its actual sound is just a more decorative sound. for the prominent native sound. This technique is relatively common in national wind music. Although it is not clearly marked on some traditional scores, it can be used flexibly in actual performance.

Generally speaking, too fast and exciting music is not suitable for use, and it is mostly used for slow and melodious passages. The fingers should not be raised too high, and the movements should be fast and flexible. Duplication is the overlapping of several sounds, which plays a decorative role. There are several types of duplication, such as second, third, and fourth. In terms of hearing, the main tone is the main tone, and the decorative tone is not heard, but the original tone is enriched. .