Zaju, a unique dramatic genre of the Yuan Dynasty, grew out of the northern zaju of the earlier Song Dynasty. Originally drawing on popular local performing styles of the north, it later absorbed zhugongdiao, a kind of song-speech drama with mixed modes of musical tunes, as well as scores / scripts performed in brothels by courtesans of the Jin Dynasty. Well-known playwrights like Guan Hanqing in the early Yuan period refined and formalized these various styles into this unique dramatic genre. Zaju is made up of four acts, each with sets of songs starting from the same gongdiao note, and sung by the principal female or male performers. The gongdiao note changes with each act. The plots are complete and well-constructed, while the lively and interesting characters rely on a rich repertoire of dramatic gestures and expressions. Dadu, capital of the Yuan Dynasty, was a prosperous center of economic activity where scholars and performers mingled well, which encouraged the rapid growth of the zaju genre. However, the style declined together with the Yuan Dynasty and by the following Ming Dynasty, it had been replaced by other operatic and performing genres.

Music follows the trends of political governance, and dramas too change with the preferences of the times. The scripts used in brothels later evolved into zaju. (Hu Zhiyu: Text Presented to the Entertainer Song)

In the Tang period, there were strange tales like unofficial histories written by scholars often for entertainment and light conversation. Only by the Song Dynasty did the Southern Opera consist of songs, recitation and comic gestures and dialogues. In the Jin, brothel scripts and zaju were combined. In our dynasty, the two are separated into distinct forms. (Xia Tingzhi: Preface to Biographies of Courtesans)