"Sing Bangzi when you win, and Erhuang when you lose." Cantonese opera Erhuang, one of the two major singing systems, has a more desolate and depressed melody. Today we will introduce and demonstrate Erhuang Sanban. Erhuang knurling, also known as "hechi knurling", is divided into seven characters and cross sentences, and can also have active sentences. The characteristic of knurling is that it has melody and no dingban. The actor sings the lyrics first, and the music is accompanied by the music according to the scale sung, creating the effect of singing first and playing later.