military command and replace him with Yan Yu, a friend of the eunuch Huang Hao. Zhuge Zhan's memorial to Liu Shan was preserved and was still available by the time of the Jin dynasty. However, it is not known whether Liu Shan heeded Zhuge Zhan's advice, because Jiang Wei did not return to the Shu capital, Chengdu, after his failure in the last of the 11 campaigns, presumably because he knew that the people of Shu were increasingly resentful of him. Liu Shan also compromised Zhuge Zhan's proposal to switch from an offensive stance against Wei to a defensive one, because he had earlier replaced Wei Yan's tried-and-tested defensive layout with a high-risk-high-reward strategy by Jiang Wei. Previously, the Shu general Wei Yan had invented a defensive strategy to hinder and repel invading forces by setting up "covering camps" on the outskirts and exits of trails leading to Hanzhong Commandery, a strategic location on the road into the Shu heartland. Even after Wei Yan's death, Liu Shan had followed this arrangement, which allowed the Shu forces to successfully keep Wei invaders out every time. However, Jiang Wei argued that Wei Yan's design "could only repel the enemy but not reap big profits." Hoping to score a decisive victory, Jiang Wei proposed to abandon the camps set up by Wei Yan and vacate all the passes in the Qin Mountains, so an invading Wei army could be lured deeper into Hanzhong Commandery, where the weary expedition force could be blocked and rendered vulnerable to a Shu counterattack upon retreat. Jiang Wei claimed his arrangement could achieve a decisive victory previously unimaginable when they had just defended along the Qin Mountains. Since Jiang Wei's analysis had sound logic and merit, Zhuge Zhan did not oppose dismantling Wei Yan's intertwined fortifications. Futile effort to defend Shu In early 263, Jiang Wei requested reinforcements from Chengdu after he heard that the Wei government had put the general Zhong Hui in charge of military affairs along the Wei–Shu border. However, Liu Shan believed in Huang Hao's witchcraft, according to which destiny dictated Wei that would not attack. Liu Shan did not inform Zhuge Zhan of Jiang Wei's warnings. Nevertheless, Liu Shan did send reinforcements before the Wei invasion commenced. When the Wei forces started advancing towards Shu in September 263, the first half of Jiang Wei's plan worked – the Wei forces marched unopposed until