The discourse on pitches for the Guqin has persisted for millennia without being substantiated by evidence-based research.This treatise draws evidence from various sources,such as Qin Yuan Yao Lu Materials,to establish that Qu Zhan's"Qin Sheng Lyu Tu"is the earliest foundational work on the Guqin's pitch distribution system.Prefaces and odes from the original work have not only been preserved to this day but also confirm Qu Zhan as the pioneer of this study.Through corroboration with other historical sources,this paper establishes that Qu Zhan was a Guqin virtuoso of the early Tang Dynasty and the grandson of King Qu Wentai of Gaochang,countering the six-decade-long misconception among the Guqin community that mistakenly identified him as a monk from the Southern Dynasty.The existence of two other coeval works by different authors,"Qin Sheng Lyu Tu"(same title but different content)and"Qin Sheng Yun Tu,"however,has contributed to the ambiguity in the relationship between the three works.Through research of relevant historical sources,this paper analyzes the content and evolution of the three works enumerated above and expounds on the discovery that Qu Zhan's"Qin Sheng Lyu Tu"had always been missing from official documentation until the Southern Song Dynasty when it was written and published under the same name by Wang Dali of the same era.