Steal The Firewood From Under the Pot
When faced with an enemy too powerful to engage directly you must first weaken him by undermining his foundation and attacking his source of power.
Legendary Era Japan
Japan's ancient hero Yamato Takeru was one of the eighty children of emperor Keiko. One day he was sent to kill a notorious outlaw who was such an expert swordsman that all who had gotten in his way were killed. Yamato Takeru did not intend to duel with the bandit and pretended to be ignorant of the man's reputation in order to befriend him. They became such good friends that they even went swimming together on a regular basis. When Yamato Takeru was assured the bandit harbored no suspicions he was ready to act. One day when they went swimming he brought with him a wooden sword that he hid in his travel kit. They were in the habit of racing each other around a small island but this time while they were racing Takeru let the bandit take the lead and, once he was out of sight behind the island, Takeru swam back to shore and quickly replaced the bandit's sword with the wooden one. After they had gotten dressed Takeru turned to the bandit and revealed his true purpose. The bandit immediately went for his sword, but the wooden sword had become wedged in the scabbard. While he was struggling to draw the wooden sword, Takeru took the bandit's head off in a single stroke.