1. During the Warring States Period, famous soldiers came forth in large numbers, and military strategists came forth in large numbers. Who can use these people to the extreme and have the strongest natural fighting capacity? Looking at the six countries, none of the peerless stars such as Wuqi, Sun Bin, Li Mu and Le Yi can do their best for their country. Pang Juan, Tian Dan, New Ling Jun, Lian Po, etc. all countries are poor in employing people. In Qin, everyone played to the extreme, except Tian Lei, who was given death before reunification.

2. Qin's basic industry is stable, which is also a factor that can support him to always have strong combat effectiveness. Qin is located in the northwest, so there is no need to worry about being attacked between Scylla and Charybdis. Basic industries have developed steadily. When countries were submerged by years of war, Qin still had strong reserve resources.

3. There are many things. Shang Yang's political reform has always been regarded as a very important link. But in the chaotic Warring States period, this factor is not worth mentioning. Just like in World War II, France was strong, but it was forced by Germany and died instantly.