This article interprets Sun Tzu’s idea of building favorable strategic momentum via the Battle of Changping. Qin secured victory through diplomacy, logistics and psychological tricks before Bai Qi’s final strike, proving momentum shapes decisive wins.
Li Si refutes Han Fei, arguing Han is a hidden threat to Qin. Its submission is fake; attack it first, or it may ally with rivals and endanger Qin.
Han Fei advises Qin: use diplomacy to win Chu/Wei, ally with Han, strike Zhao. War is risky; reckless moves isolate Qin and court disaster.
Han Fei warns Qin: attacking loyal, weak Han is a mistake. Ignore Zhao’s threat, drain strength, empower rivals, and risk unification failure.