Quick questions on Qin Shi Huangdi and the unification of China 221 BC: HSC Ancient History

Qin's conquest was guided by a coherent strategy, not improvised. The inherited policy of "befriend the distant, attack the near" (yuan jiao jin gong) kept the far states neutral while Qin destroyed its nearer neighbours one by one, so its enemies never formed an effective united front (the "vertical alliance", hezong, that the other states periodically attempted). The strategist Wei Liao, who came to Qin around 237 BC, urged King Zheng to spend gold freely bribing the powerful ministers of rival courts to break these alliances from within, reportedly estimating the whole effort would cost no more than a few hundred thousand catties of gold. The chief minister Li Si, a Legalist and former pupil of the philosopher Xunzi, is credited with directing the bribery or, where bribery failed, assassination of leading men in the other states.

<!-- Diagram: concept diagram of the invention of the imperial title Shi Huangdi in 221 BC | reviewed 2026-07-01 --> <svg class="fig" viewBox="0 0 393 396" role="img" aria-labelledby="quc-ti-t quc-ti-d"> <title id="quc-ti-t">The invention of the title Shi Huangdi, 221 BC</title> <desc id="quc-ti-d">An owned concept diagram. Two source boxes at the top: the legendary Three August Ones, contributing the word huang meaning august or sovereign, and the legendary Five Emperors, contributing the word di meaning emperor or divine high ruler. Arrows lead down from both into a central box, huangdi, the new compound title August Emperor. An arrow leads down to a final box, Shi Huangdi, the First August Emperor, proclaimed in 221 BC.

The nearest and weakest of the six fell first. The Qin commander Nei Shi Teng overran Han and captured its king, and the territory was reorganised as Yingchuan Commandery, the first of the six states to be annexed outright.

Zhao was militarily formidable, defended by the able general Li Mu. Unable to beat him in the field, Qin bribed the Zhao minister Guo Kai to slander Li Mu as a traitor; the Zhao king had him executed in 229 BC, and Wang Jian then crushed Zhao's armies and took the capital Handan in 228 BC. A prince fled north and held out at Dai until 222 BC.

Wang Jian's son Wang Ben besieged the Wei capital Daliang and, unable to storm its walls, diverted river waters to flood the city until the walls collapsed and the Wei king surrendered.

Chu was the largest of the six. A first invasion under the young general Li Xin, with around 200,000 men, was routed by the Chu general Xiang Yan. King Zheng then recalled the veteran Wang Jian, who had insisted 600,000 men were needed; with that army Wang Jian defeated Chu and captured its king in 223 BC.

Yan had already provoked Qin with the Jing Ke assassination attempt of 227 BC (below). Qin took the Yan capital Ji in 226 BC, driving the king into the far northeast (Liaodong), where Wang Ben finally captured him in 222 BC.

Qi had stood aside while its neighbours were destroyed, and its chief minister Hou Sheng had been bribed by Qin. Left alone and unprepared, Qi surrendered to Wang Ben's army in 221 BC almost without a fight, completing the unification.