During Cao Rui's reigns, there were also many battles waged against the other rival empire, Eastern Wu. The very first came only two months after Cao Rui had become emperor in 226. It was during that campaign that Cao Rui showed his acumen for judging a situation correctly—believing that by the time that reinforcements could be sent, Eastern Wu's monarch Sun Quan would have already withdrawn, and therefore sending reinforcements was pointless. Throughout his reign, he would generally take a similar stance during campaigns against Eastern Wu as he did with Shu Han — head east personally to be close to the theater of the war, while remaining some distance away from the frontlines, which also proved to be effective. He also entrusted the southeastern border to the capable Man Chong, and Man's stewardship averted many disasters.