2 Background and methodology The foundational form of the pentasyllabic regulated verse was established during the Early Tang dynasty, and since the end of the last century, this has become a consensus among scholars (Kwong, 1990; Guo, 1983). By the time of the High Tang period, Du Fu (712–770) not only cemented the prosody of the heptasyllabic regulated verse but also broke away from its rigid formal constraints, capturing the spirit and key elements of the form (Yeh, 1965). He ultimately perfected and transcended the heptasyllabic prosody (Hirata, 2012, 2013), paving the way for later poets during the Song dynasty. However, cur- rent research on Du Fu’s versification largely remains at the illustrative stage and lacks systematic analysis. For instance, Lu (1962) merely conducted a sta- tistical analysis of the occurrences and positions of various prosodic forms in Du Fu’s pentasyllabic and heptasyllabic poems, without delving into the signif- icance of these forms from a prosodic mechanics perspective, nor considering their distribution across different phases of Du Fu’s poetry. Yeh (1965) divided Du Fu’s heptasyllabic poems into four phases, though this segmentation is not without controversy. With the rapid development of digital humanities, reana- lyzing a vast amount of poetry through databases and statistical software is no longer a daunting task. Digital humanities can swiftly provide new answers to the following questions: Are there areas for improvement in the statistical methods used in previous research? Is the segmentation of Du Fu’s poetry into different phases reasonable from the perspective of understanding the evolu- tion of Du Fu’s prosody? What is the significance of the variations in Du Fu’s prosody across different phases in the context of the overall development of recent style prosody in the Tang dynasty? Before proceeding to the statistical analysis, it is necessary to explain the theo- retical basis for analyzing the prosody in this chapter. Linguists have reanalyzed the rules and principles of regulated verse using linguistic theories, leading to various models. However, these models vary in their ability to interpret standard regulated forms and even more so for their variants (Duanmu, 1990; Siu, 2017). Downer and Graham (1963), which proposed the existence of the ABA and xy systems within the regulated verse, remain the most effective models for explaining recent style prosody to date. “In my later phase I gradually get more precise with poetry’s rules?” Du Fu’s recent style prosody revisited 1 Siu Chun Ho and Chau Ka Chun DOI: 10.4324/9781003399261-3