The bassoon is a transposing instrument.

The bassoon is a traditional Chinese national musical instrument, also known as Bawu, Baula, etc. It is a woodwind instrument made of bamboo or wood and usually has eight sound holes and a blow hole. One of the characteristics of the bassoon is that it can change the pitch by moving the finger holes, so it is classified as a transposing instrument. When playing the bassoon, you need to control the pitch and timbre through the opening and closing of the finger holes and the strength of the blowing. Players can play different scales and tones by moving their fingers to change the pitch. This transposing characteristic allows the bassoon to adapt to different musical repertoire and modes.