The Longzhong Plan (隆中對) is the name given to a strategic plan given by the third century Chinese tactician and administrator Zhuge Liang. It formed the basis for the grand plan of the warlord Liu Bei and later the Three Kingdoms state of Shu. In essence it envisaged the securing of a viable regional base in southern China, and then a two-pronged attack to conquer the north. Though the plan was directed at the powerful Wei state, the ultimate aim of reunifying the empire of the fallen Han Dynasty necessitated the eventual destruction of Sun Quan's regime of Wu in the east.
Zhuge Liang joined Liu Bei as moushi (謀士), an advisor on strategic matters, in 207. According to Sanguo Zhi, it was at this time that he outlined the Longzhong Plan. The plan envisaged that Liu Bei would take over Jing and Yi provinces, both of which were ruled by relative incompetents. The Longzhong Plan noted that Cao Cao controlled the North China Plain, which was key to mastery of China, and that Sun Quan held the lower Yangtze River region, known as "Jiangdong". In view of this, a move to occupy Jing and Yi was vital for success. The essential outlines of the plan held remarkable foresight in envisaging the tripartite division of China. The other crucial aspect of the plan was the proposal for forming an alliance with Sun Quan in order to deter and resist the more powerful and intimidating Cao Cao. Other minor aspects included the institution of economic, legal and administrative reforms as well as developing cordial relations with the non-Han people located in the west and south. Such a policy would reduce resistance and increase much-needed manpower and economic resources. The culminating clause was a two-pronged northern campaign which would end in the seizure of the North China Plain and the reestablishment of the Han court.
One advance would be from Yi in the west, north through the Qin Mountains, which debouches into the Wei River valley and achieving a strategic position in the west from which to dominate the great bend of the Yellow River and the Guanzhong region. The second advance would be from Jing north toward the political centre of Luoyang and the surrounding plains. Such a campaign would presumably occur at an opportune moment of destabilisation of Wei but that moment was not specified. Nor was the role of Sun Quan in the offensives identified; though it would be assumed that he would tie down at least some of Cao Cao's forces.