Capo (English: Capo) is used to adjust the tone of the guitar, is a commonly used auxiliary tool in folk guitar playing, can be suppressed during the transposition to make the tune increase the corresponding interval, so that it is in harmony with the singer's voice, and Playing with the original fingering method greatly reduces the difficulty of transposition. Now, it is widely used in the performance of flamenco guitar, classical guitar and folk guitar. When used for solo tracks, the capo is often placed between the first to fourth fret, with the highest frequency being placed in the second fret. The use above the fourth fret is basically only found in accompaniment.