Take a drastic measure to deal with a situation

Explaination: The idiom literally means to take away the firewood from under the cauldron.  As figure of speech it indicates to remove the ultimate cause of trouble. Once water has been boiled, in order to make water temperature go down, the most essential solution is to put the fire off, namely to remove the firewood. As for military affairs, this means not to antagonize the powerful enemy face to face, otherwise, we should avoid its advantage and abate its arrogance, and finally win the victory.

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During the reign of Han emperor Jing Di in the year 154 BC, the prince of Wu, Liu Bi, and the prince of Chu,  joined forces with seven other states to stage a rebellion. They first attacked the state of Liang.

Han Marshal Zhou Yafu felt that the Wu and Chu forces were formidable and could not be easily beaten in a clash. But if their supplies were cut off, they could be defeated and the siege of Liang would be lifted.

Zhou Yafu made a detour around the enemy and managed to arrive at Yingyang before the enemy supplies did.

Zhou Yafu himself withdrew to set up camp at Maoyi to sieze the enemy's provisioons and to seal off their supply route. He ordered his men to fix crossbows around Daying and to hold their ground when the enemy attacked.

Just as the princes of Wu and Chu were fiercely attacking Liang's capital, they recieved bad news, "Zhou Yafu had sealed off their food supply route and siezed their provisions." The rebels panicked and had to give up attacking Liang. They attacked Maoyi but failed to take it and their supplies ran out. Morale was low.

The troops were unwilling to fight and within three months, the rebellion collapsed.

In 200 AD, Yuan Shao, the most powerful warlord of the north, amassed more than 100,000 troops and marched from Ye on Xuchang. To defend against the invasion, Cao Cao placed 30,000 men at Guandu, a strategic landing point on the shore of the Yellow River which Yuan Shao's troops had to secure en route Xuchang.

With a few diversionary tactics, Cao Cao managed to disorient Yuan Shao's troops as well as kill two of Yuan Shao's most capable generals, Yan Liang and Wen Chou. The morale of Yuan Shao's troops suffered a further blow when Cao Cao launched a stealth attack on the former's food store, Wu Chao. Many more of Yuan Shao's men surrendered or deserted than were killed during the ensuing battle. When Yuan Shao eventually retreated back to Ye in the winter of 201, he did so with little more than 800 light cavalry.