In the spring of the thirteenth year of Zhouzhuang (684 BC), Qi sent troops to attack Lu. Cao Gui, the counselor of the State of Lu, requested to join the army and got the consent of Duke Zhuang of Lu. The two armies fought in Changshou (now north of Qufu, Shandong, northeast of Laiwu). The two sides lined up, and Duke Zhuang of Lu was eager to beat the drums and was stopped. The Qi army relied on its strength and was eager to win, so it beat gongs and drums and launched an attack. Duke Zhuang of Lu accepted Cao Gui's advice and made a strict defense, earlier and earlier. The Qi army beat drums three times in a row, but failed to break through the defense of the Lu army. Instead, I suffered a lot and my morale dropped. Cao Gui, seeing the time was ripe, suggested that Duke Zhuang of Lu beat drums to fight back. Lu army rushed to the enemy with high momentum and soon washed away the battle of Qi army. When Duke Zhuang of Lu saw that the Qi army was defeated, he was anxious to order the pursuit of drums and was discouraged. Cao Gui got off and carefully observed the rut left by the Qi army. Standing on the crossbar of the chariot overlooking the retreat of the Qi army, he agreed to pursue. As a result, the Lu army hit the Qi army hard and won the battle of the long spoon.
After the war, when Duke Zhuang of Lu asked him why he could win this battle, Cao Gui replied, "Fighting depends on courage. When the drum is played for the first time, the morale is the strongest; When the drum was played for the second time, morale began to decline; When I beat the drum for the third time, my morale was completely gone. After the three drums of the Qi army, morale has been lost, and our army is in high spirits. The morale is strong, and naturally it is to defeat the Qi army in one fell swoop. " This idiom comes from this allusion, when it is full of enthusiasm.
Then, it analyzes the reasons for not pursuing immediately, saying: Qi is a powerful country after all, and we should not treat it lightly, but we should be wary of its feint and ambush. Later, when I saw the rut marks when they retreated, I saw their flags stagger, so I boldly suggested pursuing them. Through golden drums and flags, Cao Gui got a lot of information! It is with this information that he can make the right decision and finally win the battle.