倾柯卫足

Explanation: "Zuo Cheng Kung Seventeen Years": "Zhong Ni said: 'Martin Zhuangzi known as Kwai, Kwai can still guard their feet.'" Du Yu Note: "Kwai Japanese dumping leaves to cover the roots." Later, because of "dumping Ke Wei enough" means good at protecting themselves. 　　Source: "Zuo Cheng Kung seventeen years," said Zhong Ni 'Martin known as Zhuangzi Kwai, Kwai can still guard their feet. '"Du Yu Kwai dumping leaves note to Japan to cover the roots."