The so-called ability to unify troops is the ability to lead troops to fight. Let's compare Wang Jian's and Han Xin's ability to unify troops from three aspects: soldiers' quality, strategy and tactics, and military achievements.
First, the quality of soldiers.
Wang Jian, a general of Qin State, was the absolute main force in the war of Qin Shihuang's unification of the world. Six countries in the East, except South Korea, were wiped out by Wang Jian and Wang Ben, and Wang Jian's men were Qin Jun, the teacher of the tiger and the wolf. He had many years of war experience, was well trained and was inspired by the military rank system.
Qin Jun's soldiers mainly came from Guanzhong and Bashu, which were the core areas of the Qin Dynasty. They have a high loyalty to the state of Qin. These soldiers can also be called Qin people. They are all fighting for the state of Qin, and they can also exchange the meritorious military service for titles in the war. This is the only way for them to be promoted from the bottom, so the soldiers are very enthusiastic about fighting.
Han Xin is a general worshipped by Liu Bang. After Liu Bang was defeated in the Battle of Pengcheng, Han Xin was allowed to lead the troops to fight alone. What Liu Bang gave to Han Xin were all recruits recruited from Guanzhong and those who took refuge in Kanto. Most of them have no combat experience, only middle-level officers have experience, and they are Liu Bang's cronies.
Regardless of combat experience or military quality, Han Xin's quality is not as good as Wang Jian's Qin Jun. However, in the war, Han Xin and Wang Jian are invincible. Relatively speaking, Han Xin is more difficult, and commanding new recruits needs to train some basic military qualities and practice array methods, which are all in the charge of Han Xin, so Han Xin has the upper hand.
Second, the strategy and tactics
The wars commanded by Wang Jian were all in the war of unifying the six countries of Qin. At this time, the strength of Qin was greater than that of any other country, and it was far beyond it. Therefore, Wang Jian basically beat the weak with strength, and Wang Jian used strategy in addition to strength. The first battle was to destroy Zhao, and the second was to destroy Chu.
In the First World War of Zhao State, Wang Jian played against Li Mu, a famous soldier of Zhao State, without any advantage. After a year of confrontation, Wang Jian can't perish. Instead, he replaced Li Mu with a deviant one, and Zhao was finally destroyed. With Li Mu at home, Wang Jian can't destroy Zhao.
In the First World War of Chu, Wang Jian led a total of 600,000 troops of the State of Qin. Instead of storming blindly, he fought a war of attrition with the Chu army. He didn't fight first, mainly to kill the morale of the Chu army. When the Chu army was lax in its will and soldiers were lax, Wang Jian led an expedition to defeat Chu in World War I.
Han Xin's strategy and tactics are completely different. Every battle in Han Xin is a classic battle. For example, the destruction of Wei is a diversion. For example, in the last battle, the flag was changed. No one can succeed in this strategy except Han Xin, because the risk is too great. For example, the battle of destroying the dragon cut halfway is also a very risky winning strategy. If you don't handle it well, or meet an opponent who sees through the strategy, you may fail.
Wang Jian is characterized by a "stable" character, while Han Xin is characterized by a "dangerous" character. Relatively speaking, Han Xin's strategy and tactics are better. Although dangerous, as long as you win, the result will be considerable, and Wang Jian's strategic and tactical characteristics are stability and no risk.
Third, military achievements.
Wang Jian, the general of Qin State, was promoted by the military. He was also a general in World War I, who fought many battles and was invincible. Wang Jian's achievements are also very high, and he destroyed the five eastern countries with his son, which is unparalleled. Han Xin didn't achieve as much as Wang Jian, but Han Xin's victory was more valuable, because all the wars in Han Xin were classics of defeating the strong with the weak, except the battle of beggars' gangs.
It is normal to bully the weak, and it is special to defeat the strong with the weak. Relatively speaking, defeating the strong with the weak is more admirable and capable, so Han Xin's ability to unify troops is stronger than Wang Jian's.