Along with the state of Yan, Zhao was among the weaker states at the beginning of the period. Marquess Lie of Zhao was noted for several reforms; however Zhao was greatly strengthened during the reign of King Wuling of Zhao. Horseback culture from Xiongnu was adopted; Cavalry significantly comprised the troops of Zhao.
Furthermore several brillant military commanders of the whole period appeared concurrently, including Lian Po, Zhao She and Li Mu. Lian Po were often recorded defending the Qin. Zhao She was most active in the east; he was well known for his invasion of Yan. Li Mu was responsible for defending the Huns.
Zhao demonstarted its enhanced military prowess in the conquest of the ethnic state of Zhongshan and annexations in neighboring states of Wei, Yan and Qin. Cavalry of Zhao occasionally intruded into the territory of state of Qi to defeat the army of state of Chu. Zhao was therefore the only state to oppose the mighty Qin during the closing years of the period. Their inevitable clash precipiated in the bloodiest battle of the whole period, Battle of Changping in 260 BC, regretfully resulting in a rout of Zhao troops. Although the relieving forces of Wei saved Handan from a follow-up siege by the victorous Qin, Zhao would never recover from the huge loss of men in the battle.
In 229 BC, invasions led by the Qin general Wang Jian was oppossed by Li Mu and his subordinate officer Sima Xiang until 228 BC. According to some accounts, King Qian of Zhao ordered the execution of Li Mu and relief of Sima Xiang due to disloyal advices of court officials and Qin infiltrators, resulting in eventual loss of Zhao. Other sources noted the obsolete and incompetent Zhao troops against Qin. King Qian was captured by Qin in 228 BC, the year of conquest of Zhao by Qin. Prince Jia, the step-brother of Qian, proclaimed king at Dai Commandry and led the last attested defensive Zhao forces. The regime lasted until 222 BC when Qin army captured him and squashed his forces at Dai.
List of Zhao rulers