Qin's wars of unification participant Qi
First Emperor Ying Zheng
In 238 BC, Ying Zheng, the King of Qin, took over the reins of power after eliminating his political rivals Lü Buwei and Lao Ai. With help from Li Si, Wei Liao (尉繚) and others, Ying Zheng formulated a plan for conquering the other six major states and unifying China. The plan, which focused on annexing each state individually, was based on "allying with distant states and attacking nearby ones", one of the Thirty-Six Stratagems. Its key steps were to ally with Yan and Qi, deter Wei and Chu, and conquer Han and Zhao.