The Battle of Hongdu was a war between Zhu Yuanzhang and Chen Youyi, when Chen Youyu personally led a large army to attack Hongdu, and Zhu Yuanzhang's nephew Zhu Wenzheng, as a major defender of the city, was stunned that he had been defending the city for 85 days, and finally tried to protect Hong, and Chen Youyu's army had to withdraw.
Hongdu City, also known as today's Nanchang, Jiangxi, originally belonged to Chen Youyi's territory, but in the twenty-second year of Zhizheng (1362), Hu Tingrui (Hu Mei), the minister of Jiangxi Province, defected to Zhu Yuanzhang, and the Hongdu he was stationed in also belonged to Zhu Yuanzhang. Hongdu was changed by Zhu Yuanzhang's name, and was called Longxing during The Occupation of Chen Youyi.

The strategic position of Hongdu was very important, and it was a place where soldiers and families had to fight, so after taking Hongdu, Zhu Yuanzhang sent his nephew Zhu Wenzheng as the governor of Dadu, and the general Deng Yu to participate in the politics of Jiangxi Province and garrison Hongdu. It can be seen that Zhu Yuanzhang attaches great importance to Hongdu, and so does Chen Youyu.
Chen Youyu in the middle reaches of the Yangtze River was stronger than Zhu Yuanzhang, and he was bent on annexing Zhu Yuanzhang, but this was good, and there was no way to do anything, and Hongdu, which was in an excellent strategic position, was also lost. This made him very annoyed, and he wanted to get Hong Du back all the time.
Therefore, in the twenty-third year of Zhizheng (1363), Chen Youyu personally led an army of 600,000 people and besieged Hongdu. At this time, Zhu Yuanzhang really did not care about Hongdu, he was fighting against Zhang Shicheng of Eastern Wu, and the war was also very fierce. However, at that time, Zhu Yuanzhang also analyzed that even if he sent troops to assist, it would probably be a drop in the bucket, after all, the gap between the balance of forces was too big.
Therefore, Zhu Yuanzhang could only order his nephew to die in Hongdu. Zhu Wenzheng was not a clumsy disciple, he only knew the gongzi brother who spent the day and the earth, this person's ability was very strong, not to be underestimated, and at the same time, there was also a very strong Deng Yu who guarded the city with him, and the main general was not weak on this side.
Faced with a tense situation, Zhu Wenzheng ordered the defenders to hold Hongdu to the death, and he personally commanded his own troops, climbed the city tower, stood with his comrades-in-arms, and used large knives and his flesh and blood to resist the repeated onslaught of 600,000 enemy troops.
Deng Yue is not easy to provoke, he is good at using firearms, so Deng Yu led his troops to take turns shooting at the enemy troops who attacked the city with muskets, it can be said that after several attacks, Chen Youyu's army suffered heavy losses, and did not dare to move forward in the face of powerful firearms.
Zhu Wenzheng's composure to fight the battle consumed a large number of Chen Youyu's Han army, and no matter how many Chen Youyi's troops were, they could not afford to consume them. For three months, he was stunned that he did not fight in, which made Chen Youyu very depressed, and the morale was also very bad, so he had to withdraw from the siege.
Zhu Yuanzhang's side also reorganized the armament war, fully supported, and then fought with Chen Youyu at Poyang Lake, and as a result, Chen Youyu was completely defeated, and he himself was killed.