Openly Repair The Walkway, Secretly March to Chencang
Attack the enemy with two convergent forces. The first is the direct attack, one that is obvious and for which the enemy prepares his defense. The second is the indirect, the attack sinister, that the enemy does not expect and which causes him to divide his forces at the last minute leading to confusion and disaster.
Muromachi Period Japan
In 1560 one of Japan's greatest warlords, Oda Nobunaga, then still a minor commander, marched his force of 2,000 men to stop the incursion of a rival warlord Imagawa Yoshimoto. Even though Nobunaga was outnumbered twelve to one he set out humming a tune. Nobunaga's scouts reported that Imagawa was resting his troops at a village that was nestled near a narrow gorge that Nobunaga knew would be ideal for a surprise attack. The scouts further reported that Imagawa's troops were celebrating and viewing the heads taken in a previous battle. Nobunaga devised the following ploy. He made camp some distance away from the village. He placed numerous flags and had straw dummies made to give the impression that a large host had arrived. Imagawa's forces thus expected an attack to come from the direction the enemy camp. Meanwhile Nobunaga's troops secretly made a forced march in a wide circle in order to come up from behind the Imagawa encampment. Weather favored Nobunaga's scheme for late in the day there was a heavy downpour. Taking advantage of the foul weather, Nobunaga's troops launched a sudden attack from the rear. So unexpected was this attack that Imagawa a first thought that a brawl had broken out among his own troops. Only when he saw two enemy Samurai charging towards him did he realize he was under attack. The realization came too late and Imagawa was beheaded and his troops scattered. The battle lasted only a few minutes but it made Oda Nobunaga's reputation and he quickly rose in power until he became one of Japan's greatest warlords.