1, Xiang Yu is too big. At that time, Xiang Yu's army was about 400,000, and Liu Bang's army was about100,000. And Xiang Yu just defeated Qin Jun's main force, which made him sublime in the world, and the vassal surrendered, and the world just let him pay for it himself.

2. Liu Bang took Xianyang and sent it to Xiang Yu. He abandoned the agreement of Wang Zhi who entered Xianyang first and retreated to Xianyang. Such a move is normal, everyone will think that he is a man of righteousness, and it is absolutely a moral mistake to kill him. Besides, Liu Xiang is a sworn brother, and Xiang Yu has no intention of killing him. That's what Fan Zeng meant.

3. That is to say, Liu Bang's 100,000 troops are basically Liu Jiajun. More importantly, Liu Bang's troops have been resting in Guanzhong for two months. A considerable part of Xiang Yu's 400,000-strong army is a vassal army of all stripes. Although controlled by Xiang Yu, he may leave Xiang Yu at any time. In the "Battle of the Julu", all the vassal armies have precedents of sitting on the sidelines. These 400,000 miscellaneous brands have come from afar, and their combat effectiveness is almost not dominant. Perhaps Xiang Yu has this consideration, so he will accept Liu Bang's gift calmly.