堪輿「八會」異考辨──利用出土數術文獻及實物驗證傳世典籍之一例

Analysis of the Interpretations of the“Eight Assemblies”of Kanyu堪輿: Using Unearthed Mathematical and Divination Literature and Objects to Verify Ancient Documents

本文採用「二重證據法」，以數術類文獻為研究對象，結合傳世文獻、出土文獻及出土實物對古堪輿術中的重點概念「八會」進行討論。古堪輿術與古代「斗建之術」密切相關，「八會」，又稱「陰陽大會」、「八合」、「會」等，是指根據北斗雌雄神運行規律所推算出來的八個大小相會之日。文章首先詳細梳理了傳世文獻中關於「八會」的相關記載，發現古書中所記「八會」系統分為兩類，一類主要見於《周禮》和《淮南子》；一類見於《堪輿經》佚文。兩類「八會」系統的差別從表面上看在於大會日所屬月份不同，然實際上是會日推算方法相異，而這樣的「相異」又是在錯誤理解前人注疏基礎上所引發的。根據我們對這一問題的梳理辨析，認為見於《堪輿經》佚文的第二類「八會」系統更為可信，再輔之以北大漢簡《揕輿》篇相關記載為證，則更確鑿無疑。另外，我們從堪輿式圖與「八會」的聯繫出發，以出土文獻及實物為證，指出了堪輿家所用的特殊的右行十二辰式圖乃是與其對「八會」的格外重視有關。對此問題的探究，不僅可以讓我們深入瞭解堪輿術中所謂「八會」的具體內涵及其發展演變過程，亦可充分感受數術文獻特殊的複雜性及其邏輯的嚴密性。

The present article adopts“dual attestation”and uses literature on mathematics and divination to discuss the key concept of the“eight assemblies”八會of ancient kanyu堪輿(“heaven and earth”or“geomancy”) by combining ancient documents, both passed down and newly excavated, and unearthed objects. Through a detailed comparison, this article discovers that the system of the eight assemblies recorded therein is divided into two categories: one is mainly found in the Rites of Zhou周禮and Huainanzi淮南子, whereas the second is recorded in the surviving text of Kanyu jing堪輿經. The differences between the two forms is outwardly the difference in the month of the“great assembly”大會, but in reality, it is due to the dissimilarity in the method of calculating the assembly day, a“difference”caused by the misunderstanding of previous commentaries. We have found the second system of the eight assemblies in Kanyu jing堪輿經to be more credible, in part, as it is supplemented by relevant records in the chapter Kanyu堪輿of the Peking University Western Han bamboo slips. In addition, we point out that the unique right-line twelve branches diagrams used by kanyu practitioners are related to the special importance they attached to the eight assemblies, evidenced by excavated documents and objects. This investigation into the matter not only provides us with an in-depth understanding of the specific connotations of the eight assemblies and its development and evolution processes, but also allows us to fully appreciate the remarkable complexity and rigorous logic of mathematical and divination literature.