 King Ping also ordered a very tight controls over the state's borders to catch Wu Zixu.As Wu Zixu approached Zhaoguan (), the last pass to the state of Wu, he sought the help of the physician Donggao Gong (), who recognized him as Wu She's son.Donggao Gong felt deep sympathy for Wu Zixu's plight and offered to help him escape across the border.