In 207 BC, Song Yi and Xiang Yu led the Chu army north to prepare to rescue the Zhao state, but after Song Yi arrived near Julu, he ordered all the generals not to attack. So Xiang Yu took the opportunity to kill Song Yi, with the determination of "breaking the cauldron and sinking the boat" and the Qin army on the other side of the battle to the death, after nine fierce battles, the Qin general Zhang Handan finally defeated and fled, Xiang Yu took the opportunity to attack Wang Li, beating the Qin army in the Hebei region to the ground.
After sweeping away the Qin army in Hebei, Xiang Yu led the army and the Qin general Zhang Handan to fight each other. At this time, Qin II heard that Zhang Handan had lost the battle, so he sent someone to the military camp to reprimand Zhang Handan, and Zhang Handan's heart felt very afraid, afraid that Qin II would relieve him of his military powers, so he sent someone to Xianyang to ask Qin II. At the same time, Zhang Handan also sent emissaries to Xiangyu's military camp to discuss peace talks, but due to the large gap in conditions and requirements between the two, the first peace talks were not successful.
At this time, the occurrence of one thing hastened Zhang Handan's surrender, that is, after the emissaries he sent arrived in Xianyang, they were left outside the city for 3 days by Zhao Gao, who was in real power at the time, which was obviously the meaning of distrusting Zhang Handan. At this time, Xiang Yu led the Chu army to defeat the Qin army near the sewage, so after careful consideration, Zhang Handan decided to send emissaries to Xiang Yu's camp again to beg for surrender. At this time, Xiang Yu and the counselors discussed and believed that the Qin army was already at the end of the crossbow, and it was completely no problem to accept their surrender at this time, so Xiang Yu and Zhang Handan met near Huanshui, and signed a surrender clause, and accepted Zhang Handan's 200,000 Qin army to surrender.
But what Xiang Yu did not expect was that these 200,000 Qin troops were a hot potato. It turned out that after Xiang Yu accepted the Qin army troops, the status of the Qin soldiers in the army was very low, and they were often bullied by the soldiers of the princes' army. So many Qin soldiers secretly discussed: "If you can follow General Zhang Handan to attack Hangu Pass, it is naturally good; But if we can't invade, then our wives and children will be slaughtered by Qin II, so what should we do?"
After Xiang Yu learned of this incident, he knew that if he did not deal with this matter in time, it would cause a mutiny in the army, so he summoned Tuobu and other important generals to discuss overnight, and finally Xiang Yu ordered 200,000 Qin soldiers to be buried alive in the south of Xin'an City overnight. In fact, Xiang Yu was not too suspicious, and his personality was not born cruel, but only to maintain the order of the army would make such a heinous treatment of the Qin army's descendants.