Abstract: The lyrics for singing in the ancient Chinese literature, in terms of stylistic form, falls into two types: qiyan (lines of regular lengths) and zayan (lines of irregular lengths). In the early Tang period, Shen Quanqi and Song Zhiwen established the versification of qiyan poetry, while the regulating course of zayan poetry began in the Middle and Late Tang Dynasty. If the unregulated zayan poetry can be defined as Qu (the later opera verse) and the regulated zayan poetry as Ci (fixed rhythm lyrics), the evolution of zayan (the verse with irregular lines) in the past thousand-odd years was following a trajectory from Qu to Ci. While it was generally accepted in the study of Chinese poetry that the regulated poetry evolved into fixed rhythm lyrics and then into the opera verse, the paper proposes that "the established view" in the past several hundred years should be regarded with respect but not accepted without reservation.

Key words: Qu evolving into Ci, Ci evolving into Qu, the Song-Dynasty Ci (fixed rhythm lyrics), the Yuan-Dynasty Qu (opera verse), the Southern and Northern Qu (unregulated verse of irregular lines)