How did emperor shi huangdi unify the people under 1 single identity

Shi Huang Di was the king of Qin, one of the several states of the period called the Warring States Period, a time of wars, anarchy and full uncertainty. The big states waged war against another and there was no strong central power to restrain them.

Then, some innovations gave an advantage to Qin: new agricultural methods and better canal building that allowed to produce more food, thus making it possible to sustain a large and powerful army; more powerful weapons such as better new bows and crossbows and a strong leadership with a clear purpose. Qin defeated all its adversaries. All those factors led to an extraordinary outcome: the first unification of China in the year 221 BCE. Qin's ruler was the first emperor, the first man who unified all the Chinese lands under one single banner.