Duck Hook
（重定向自Pruning Knife）
Duck Hook (code-named "Pruning Knife" by the military) was the White House code-name of an operation President Richard Nixon had threatened to unleash against North Vietnam during the Vietnam War, if North Vietnam did not yield to Washington's terms at the Paris peace negotiations. Duck Hook called for the possible-nuclear bombing of military and economic targets in and around Hanoi, the mining of Haiphong and other ports, air strikes against North Vietnam's northeast line of communications as well as passes and bridges at the Chinese border, and air and ground attacks on other targets throughout Vietnam.