This is an episode from the Three Kingdoms. In the third century A.D., China was devided by three powers, Wei, Shu and Wu, each controlled North China, Southwest China and South China. One year, the state of Wei set off to attack Wu and soon arrived at the Northern bank of the Yangsti River. Wu's army was just stationed at the other bank. 

Wu's commander in chief Zhou Yu decided to fend off the Wei army with arrows. He'd need some 100,000 arrows. Problem is how could he make enough arrows in such a short period of time. 

Just then, Zhuge Liang, Prime Minister of the state of Shu came for a visit. He said lightly he could get the arrows in three days. He even signed a pledge placing himself liable for punishment should he fail to complete the order. He knew he couldn't manufacture that many arrows in three days. But he asked his good friend, Lu Su, an official in the Wu court, to lend him 20boats, each lined with straw-made scarecrows and manned by 30 soldiers. He requested that Lu Su not tell anyone what was happening.

The first day passed, then the second. On the third night, Zhuge Liang invited Lu Su for a boat ride. The 20 boats were tied together with strong ropes. Zhuge's fleet sailed toward the camp of Cao Cao. A thick mist had spread over the surface of the river. People could hardly see each other on the river. When Zhuge's fleet got close to the Cao camp before dawn, Zhuge Liang ordered his soldiers to shout and beat drums to fake an attack. Zhuge and Lu Su simply sat inside one of the boats and drank wines to enjoy themselves. As soon as the Cao camp heard the shouting and drum beating, they mistook it for a surprise attack by the Zhou Yu camp. Since they could see nobody on the river, they gathered 10,000 bow men and ordered them to shoot arrows towards where the shouting and drum beating came. The front of the scarecrows was quickly shot full of arrows. After a while, Zhuge Liang had his fleet turned around to expose the other side of the scarecrows. When this side was also shot full of arrows, the day broke. Zhuge Liang ordered his soldiers to return to their base port. After they got back to their camp, they collected more than 100,000 arrows from the scarecrow