The arguments among the son of Xishu, the Prince of Dongwu and Mr. Wei in Zuo Si's Sandu Fu were actually the battle about the legitimacy of the regime in the Three Kingdoms' tripartite confrontation and the North-South confrontation. The point of the arguments was not about the location of the capital, but about what was legitimate, or the legitimacy of the regime that Jin inherited from Wei. Specifically, Shudu Fu stated the orthodox viewpoint of Shu-Han, the son of Xishu. Wudu Fu stated the cultural orthodox viewpoint of Zhou-Han, the Prince of Dongwu, while Weidu Fu represented Cao Wei's political stand that Jin descended from Wei. A record of the legitimacy of Cao Wei from the perspective of abdication must highlight the political achievements of the State of Wei, and therefore must start from the founding of the State of Wei. In terms of the location of the capital, Ye bore greater political and cultural significance than Luoyang. Therefore, in terms of legitimacy and the mandate of heaven, only Capital Ye could take on such a mission. From the perspective of cultural geography, the north-centered cultural mode of thinking which was shaped in the Zhou-Han unification period became Mr.Wei's theoretical basis of his criticisms of the son of Xishu and the Prince of Dongwu who boasted about their capitals, and of his praise of Cao Cao's establishing Ye as the capital. On the other hand, Luoyang's significance and value as the centre of a unified nation was not fully justified during the period of the Three Kingdoms. In fact, the historical mission of unifying the country was accomplished by the Western Jin Dynasty, which is another important cultural-geographical factor accounting for why Zuo Si selected Ye as his topic. In Weidu Fu , Mr. Wei gave an ''authentic'' description of Capital Ye's organizational system, local conditions and customs, and Emperor Wei and so on. The description centered round the ruler's righteousness and the ''legitimate capital and benevolent government,'' illustrating his political ethics that Jin descended from Wei.Mr.Wei's comment on Cao Wei is not only a historical evaluation of the Three Kingdoms, but also a major political issue of how the Western Jin Dynasty judged its regime. Using a literary form, Zuo Si successfully applied the political-cultural functions of Da Fu in his record of the fight for hegemony between the three kingdoms and disputes about the Western Jin Dynasty's lineage. It was an approval of the mainstream ideology of the political ethics that Wei was legitimate and Western Jin Dynasty descended from Wei. This explains Zuo Si's description of Capital Ye in Weidu Fu , and the historical and political backgrounds of the overwhelming popularity of Sandu Fu (the sensational effect called ''luoyang zhigui'' ).