The "Lü-shih ting-t'i" (Fixed Forms in Regulated Poetry), a short treatise attributed to Wang Shih-chen of the early Ch'ing dynasty, aims at providing its readers with tonal rules in the composition of regulated poems. Eight regulated poems are used in the treatise to illustrate the stringent rules governing tonal variations in regulated poetry However, the rules given in this seemingly authoritative work, which has been held in high esteem by some scholars, are neither infallible nor exhaustive, and reflect the authors readiness to make his own rules rather than deduce rules from the poetic works of the T'ang dynasty, when regulated poetry appeared and matured. This paper acknowledges the contribution of the treatise, virtually the first of its kind, to the study of Chinese regulated poetry. But more importantly, it identifies the treatise's inadequacies and rectifies its mistakes.