Zhou Yu 周㬂 was an officer of Yuan Shao 袁紹 and younger brother of Zhou Ang 周昂 and Zhou Xin 周昕. In 191 A.D. he attacked Sun Jian's camp at Yangcheng. Some historians, such as Sima Guang, believe it was Zhou Ang who attacked Sun Jian, while the Book of the Later Han says it was Zhou Xing. Rafe de Crespigny and Wu lu believe it was Zhou Yu, based on his military career.
In 189 A.D. Zhou Yu raised 2.000 men to serve Cao Cao in the alliance against Dong Zhuo. He then transferred to Yuan Shao.
When the Guandong Coalition was falling apart, Yuan Shao sent the Kuaiji native Zhou Yu to attack Sun Jian, officer under Yuan Shu 袁術. Zhou Yu, who had just been appointed as Inspector of Yu province, attacked Sun Jian and defeated him and took over his camp.
Sun Jian counterattacked and defeated Zhou Yu in multiple skirmishes, who then fled. During the battle Gongsun Yue 公孫越, who reinforced Sun Jian, was hit by a stray arrow and died.
- Historians aren't convinced it was Zhou Yu who fought Sun Jian. The History of the Later Han says it was Zhou Xing, while Zizhi tongjian says it was Zhou Ang. Based on Zhou Yu's career, Wu lu and Rafe de Crespigny seem to agree it was Zhou Yu.
When Cao Cao was rallying troops to join the campaign against Dong Zhuo in 189, Zhou Yu raised 2000 men to go to him and became Cao Cao's advisor. He later transferred toYuan Shao's camp and was named the Inspector of Yu Province (豫州).
In the Battle of Yangcheng in 191, caused by a feud between the cousins Yuan Shao andYuan Shu, Zhou Yu was commanded by Yuan Shao to attack Yuan Shu's general Sun Jian in Yangcheng. In the beginning, Zhou had the upper hand, routing Sun Jian, but Sun Jian counterattacked and defeated Zhou Yu. This venture is often mistakenly ascribed to Zhou Ang instead.
In the next year, Zhou Yu went to aid his brother Zhou Ang against an attack by Yuan Shu in Jiujiang (九江), but they were defeated. Zhou Yu returned to Kuaiji after the battle, where he was killed by Xu Gong.