In the winter of 208-209, Huang Gai fought in the Battle of Red Cliffs against Cao Cao's forces. He was a subordinate of Zhou Yu, who was the frontline commander of Sun Quan's forces in that battle. Huang Gai told Zhou Yu: "The enemy are superior in numbers in comparison with our side. I fear that we cannot last long. However, I observe that Cao Cao's ships are linked to each other. We can destroy them by fire." Huang Gai then prepared about ten "mengchong"s and "doujian"s (鬬艦; a type of warship) and filled them with the ingredients necessary for starting a fire. He then wrote a letter to Cao Cao, pretending that he wanted to surrender and defect to Cao Cao's side. Cao Cao told Huang Gai's messenger: "I only fear that this is a trick. However, if what Huang Gai said is true, I will reward him handsomely."