This dissertation provides an insightful analysis on the Dunhuang Manuscript P.2968. Negating the previous perspective that the letter was sent to Ganzhou by the governor of the Guiyi Army, it points out that the author was in fact Murong Guiying, the governor of Guazhou and that the recipients ＂Situ and Sikong＂ were Cao Yuande and Cao Yuanshen. The dissertation expounds and proves the time and possibility of the letter by analyzing the tributary issues raised in P.2968, including the road traffic in Hexi Area and tributaries during Cao Yuande's governance, and thus complements the studies on tributary issues carried out by the Guiyi Army after Cao Yijin's death.
