Sun Jian accidentally seized the Chuanguo Jade Seal and planned to take it for himself, but Yuan Shao already knew that the Jade Seal was in his hands, but Sun Jian killed him and did not admit it, which made Yuan Shao also helpless.
Sun Jian also realized that if he continued to stay, he might "lose his life", so he immediately led his army to flee to Jiangdong, but how could Yuan Shao let him escape, so he secretly contacted Liu Biao, who secretly ambushed and caught Sun Jian by surprise, and the two also formed a deep hatred since then.

Then again, although Sun Jian suffered extremely heavy losses, he also returned to Jiangdong safely. At the same time, Yuan Shao's life was not very comfortable, and he had been in Hanoi for a long time, and there was a shortage of grain and grass.
The strategist Feng Ji gave him advice, thinking that he could use Gongsun Zhan to attack Jizhou, and then he would send a message to Jizhou himself, so that Jizhou would fall into his hands effortlessly.
Although this trick fell into the well, the effect was very significant, Gongsun Zhan carried the pot, and naturally handed Jizhou to Yuan Shao.
Gongsun Zhan was greatly humiliated by this, how could he give up, so he personally led a large army to seek justice with Yuan Shao, and the two fought each other, and the paper soldiers met each other.
The reason why Yuan Shao and Gongsun Zhan turned against each other, I think we can study it from these three aspects:
<h1 class="pgc-h-decimal" data-index="01" data-track="14" > Yuan Shao treacherously and embezzled grain and grass</h1>
At first, Gongsun Zhan received instructions from Yuan Shao, that is, to let him attack Jizhou, and then he and his two sides attacked, and the two of them were to be divided equally after the attack on Jizhou. Two people contribute, and both men take what they get.
However, Yuan Shao betrayed his faith, secretly sent a message to Jizhou, played the role of a "kind person", let Gongsun Zhan carry the black pot, let his boat and car work hard, full of joy, but in the end he got nothing.
Gongsun Zhan was "played as a monkey", so teased, how can he not be angry, how can he not be angry, he is bound to seek justice.
<h1 class="pgc-h-decimal" data-index="02" data-track="17" > congdier negotiated unsuccessfully and died in Huangquan</h1>
After learning of Yuan Shao's treachery, Yuan Shao had already occupied Jizhou, and Gongsun Zhan was angry, so he sent his cousin to negotiate in an attempt to get justice and get his own place.
However, Yuan Shao had a bad attitude, ostensibly saying that he would let Gongsun Zhan personally negotiate and agree, but secretly he attacked and killed Gongsun Yue on the way back.
When Gongsun Zhan learned of this news, it could be said that he was furious, the two armies were at war, and they had not yet beheaded, why did Yuan Shao want to kill his cousin. The more he thought about it, the more angry he became, the more angry he became, so he couldn't bear it anymore and directly raised his troops to seek justice with Yuan Shao.
<h1 class="pgc-h-decimal" data-index="03" data-track="19" > to defect to loyalty and disappointment</h1>
At first, when Cao Cao was recruiting an army, Gongsun Zhan went to seek justice, and he also felt that Yuan Shao was a loyal soldier, so he strongly recommended him as an ally.
However, Yuan Shao's current behavior is really a big surprise, treachery does not say anything, and he will take revenge.
Gongsun Zhan also regretted that he had seen the wrong person, and with the anger of falling into the well, he defected to the disappointment of Zhongyi, and became angry and was bound to fight Yuan Shao to the death.
So what would be the outcome of Gongsun Zhan's battle with Yuan Shao? Sun Jian was secretly calculated by Liu Biao, will he give up?
Predict what will happen after the matter, and the point of attention will know.
Reference: Romance of the Three Kingdoms: Yuan Shaopanhe Zhan Gongsun