At the end of the Eastern Han Dynasty, the flock of heroes chased after the Central Plains, and for the various princes, although they had the heart of disobedience, before the abdication of Emperor Xian of Han, only Yuan Shu, a prince, arrogantly claimed the title of emperor. In the second year of Jian'an (197), Yuan Shu was proclaimed emperor in Shouchun, with the title of Zhongshi (仲氏), the Gongqing (公卿), and the northern and southern suburbs of the temple. Yuan Shu proclaimed himself empress dowager, appointed Jiujiang Taishou as the Yin of Huainan, placed a wide range of courtiers, and built an altar for the emperor to sacrifice to the Emperor in the north of the city. At that time, although the Han Room was in decline, the prestige of the Han Dynasty for hundreds of years still prompted many people to have the Han Room in their hearts, such as Liu Bei, Guan Yu, Zhuge Liang and others, who were loyal to the Han Room.
Therefore, Yuan Shu's act of arrogantly claiming the title of emperor naturally aroused the anger of the public. In the view of many historians, Yuan Shu's act of claiming the title of emperor was despised by the princes of the world, and Yuan Shu became the target of public criticism, and soon he was successively attacked by the rebellion and attack of Sun Ce, Lü Bu, and Cao Cao. In the fourth year of Jian'an (199), under the constant blows of Cao Cao, Yuan Shu vomited blood and died. So, the question is, when Cao Cao destroyed Yuan Shu, what was his brother Yuan Shao doing, why didn't he rescue Yuan Shu?

One
First of all, in the fourth year of Jian'an (199), under the blows of Cao Cao, Lü Bu and others, yuan Shu, who was cornered, went to Bashan to defect to his former parts Lei Bo and Chen Lan, but Lei Bo and others refused, so he returned the imperial title to Yuan Shao and wrote to Yuan Shao, asking him to take him in. In this regard, Yuan Shao agreed to accept Yuan Shu. As a result, Yuan Shu went to Yuan Shao's eldest son, Yuan Tan, who was then the Assassin of Qingzhou. In this regard, in the author's opinion, if everything goes well, Yuan Shu is likely to spend the rest of his life under Yuan Shao. However, Yuan Shu was intercepted on the road by Liu Bei and Zhu Lingjun sent by Cao Cao. Yuan Shu could not pass, and retreated to Shouchun.
In June of the same year, Yuan Shu retired to Jiangting. Soon after, Yuan Shu vomited blood and died. Of course, it should be noted that when Yuan Shu was about to be destroyed by Cao Cao, Yuan Shao only agreed to accept him, that is, he did not send troops to support Yuan Shu. In other words, Yuan Shao sat idly by as a whole about what happened to this brother. If he really rescued, Yuan Shao, who was sitting in the land of four states at that time, was fully capable of rescuing Yuan Shu from Cao Cao's men. In this regard, in the author's opinion, the reason why Yuan Shao did not rescue Yuan Shu is divided into the following points.
Two
On the one hand, in the second year of Jian'an (197), Cao Cao sent Kong Rong to send an envoy to Yicheng with the Tianzi Fu Festival, and paid yuan Shao a general, giving him a bow and arrow, a fu jie, an axe iron, and a hundred tigers, and put him in charge of the four prefectures of Jizhou, Qingzhou, Youzhou, and Hezhou to ease the contradictions between the two. From this, it is very obvious that when Yuan Shu was arrogantly proclaimed emperor, Yuan Shao officially became a great general of the Eastern Han Dynasty, and it was liu xie, the emperor of Han Xian, who was canonized. Therefore, as a great general of the Eastern Han Dynasty, Yuan Shao should quell the rebellion under the Han Dynasty.
As for Yuan Shu, who overtook the title of emperor, he was naturally the first to bear the brunt. Of course, Yuan Shao did not lead an army against Yuan Shu. However, if you really help Yuan Shu, you will inevitably be attacked by the world's soldiers, that is, since you Yuan Shao accepted the canonization of the Eastern Han Dynasty, and now you are helping Yuan Shu to usurp the title of emperor, it can be described as contradictory, allowing yourself to fall into the accusations of everyone. In other words, Yuan Shao was unwilling to make enemies of the world for the sake of Yuan Shu's brother, which inevitably required the two to draw a clear line.
Three
On the other hand, in the process of Cao Cao and others eliminating Yuan Shu, Yuan Shao was busy dealing with Gongsun Zhan, and he himself was also lacking in skill. At the end of the Eastern Han Dynasty, Liu Bei's old classmate Gongsun Zhan was belligerent and disagreed with Liu Yu, the pastor of Youzhou who advocated Huai Rou, and the contradictions between the two gradually intensified. In the fourth year of Chuping (193), Gongsun Zhan killed Liu Yu and held the emissaries of the imperial court hostage, and was authorized by the governor of the four northern states to become one of the most powerful princes in the north. Youzhou and Jizhou were close to each other, so for Gongsun Zhan, who controlled Youzhou and other prefectures, it naturally became a major problem for Yuan Shao, the pastor of Jizhou. Gongsun Zhan and Yuan Shao fought many times, initially gaining the advantage, but after the Battle of Longzhuo, Gongsun Zhan's morale was reduced, he adopted a self-protection strategy, and gradually lost the trust of his subordinates, and was finally defeated by Yuan Shao.
In 199 AD, Gongsun Zhan committed suicide, and Yuan Shao annexed the territory before Gongsun Zhan, thus sitting on the four prefectures of Youzhou, Qingzhou, Hezhou, and Jizhou, and overpowering Cao Cao and other princes in terms of overall strength. For Yuan Shao, it was difficult to obtain any substantial benefits by helping Yuan Shu, but to eliminate Gongsun Zhan was to expand his own territory.
Four
Finally, in addition, although Yuan Shao and Yuan Shu are brothers, there are too many contradictions between the two, and it can even be said that they have accumulated grudges for a long time. For Yuan Shao, it was originally a concubine, inherited from Yuan Cheng's room, and Yuan Shu was a concubine. Therefore, Yuan Shu had always looked down on Yuan Shao. However, the latter was handsome in appearance and majestic in temperament, which was very much loved by Yuan Feng and Yuan Kui, and won the support of the hero Hao Jie at the end of the Han Dynasty, and he did not look up to Yuan Shu very much. Therefore, in the last years of the Eastern Han Dynasty, when the crowds were chasing the Central Plains, Yuan Shao and Yuan Shu did not fight together, but went their separate ways after Dong Zhuo usurped power. After Dong Zhuoxi left Chang'an, Yuan Shao prepared to abandon Emperor Xian of Han and establish a new monarch to facilitate control. He chose Han Zongfu and Youzhou Mu Liu Yu. At that time, the Yuan brothers were not harmonious, and Yuan Shu had a self-reliant heart, and under the pretext of maintaining loyalty, he opposed Yuan Shao's establishment of Youzhou Mu Liu Yu as emperor.
Because of this incident, the contradiction between Yuan Shao and Yuan Shu naturally intensified even more. In this context, Yuan Shao formed an alliance with Cao Cao and Liu Biao, while Yuan Shu allied with Lü Bu, Tao Qian, Gongsun Zhan and other princes. To a certain extent, the princes of the late Eastern Han Dynasty can basically be divided into two camps: The Yuan Shao clan and the Yuan Shu clan. Of course, in 199 AD, after Cao Cao eliminated Yuan Shu, the alliance between Yuan Shao and Cao Cao officially broke down, and both were preparing for a decisive battle with the other. Therefore, in the author's opinion, Yuan Shao's behavior of sitting by and watching Cao Cao eliminate Yuan Shu is really unwise, or it is a manifestation of the lack of long-term vision. Because after the demise of Yuan Shu, it not only meant the growth of Cao Cao's power, but also caused him to lose his worries, if during the Battle of Guandu, Yuan Shu was able to attack Cao Cao in the rear, it would obviously increase Yuan Shao's chances of victory.