. . "Battle of Yanzhou" . . . "several battles" . "failure to take Yan" . "took back his territories" . "returned to take back Yan Province" . . . "Cao Cao" . . . . "Han dynasty" . . . "Victory for Cao Cao, L\u00FC Bu retreats" . "conflict broke out" . . . "war broke out" . . . . . . "China" . . . "over 10,000" . . . "Conquest of Western Yan" . . . "Battle of Yan Province" . . "Battle of Yan Province" . "his defeat against" . "L\u00FC Bu" . . "Battle of Yan" . "Battle of Yanyu" . .