Guan Yu lost Jingzhou . The main reasons were that he was too rash, arrogant, and had relatively few troops left. These three reasons led to Guan Yu being unable to win in the end, and he would also be attacked from both sides. This is indeed a relatively direct reason, because the lack of sufficient preparation will lead to the final result, which is so miserable.

1. Excessive rashness

Guan Yu would be a little rash, which would lead to him being attacked from both sides, defeated and lost. This statement is not unreasonable. The most direct reason why Guan Yu lost Jingzhou was because he was not fully prepared and directly chose to launch the Northern Expedition. Although they were able to achieve a series of achievements, the back-up reinforcements obviously couldn't keep up, which would lead to a failure in success.
2. Arrogance

Guan Yu was an arrogant and arrogant person, so he did not handle the relationship with Soochow well. Sun Quan once asked his son to propose to Guan Yu's daughter. At this time, Guan Yu not only did not agree, he actually insulted her directly and refused to get married. This behavior is really incredible, and makes Sun Quan feel shameless and very angry with Guan Yu.
3. There are relatively few troops left behind

There are relatively few cases left behind in Jingzhou. Jingzhou’s geographical location is very important. It seems that the current Hubei area is the center of our country, and it is the throat zone between the north and the south. Cao Cao, Sun Quan, Liu Bei, people in these three places will value Jingzhou more. Everyone hopes to occupy Jingzhou and take the initiative. After the death of Jingzhou and Liu Biao , everyone began to compete for Jingzhou, and the original paradise immediately turned into a place of four wars. After nearly 7 to 8 years of operation, Guan Yu also began to recruit troops again, but because there were not many troops left, it was naturally impossible to have a chance to win. From this aspect, this led to the final loss of Jingzhou, which indeed makes people feel a little regretful and helpless. I hope that some protective measures need to be paid attention to in this matter.