Shifting focus from the Sino-Vietnamese borderlands to the northern Gulf of Tonkin during the decade from the end of the First Indochina War to the escalation of the Vietnam War, this chapter views the history of state building from the seashore. Echoing land reforms and agricultural collectivitization on the borderlands, fishery reforms and collectivization toppled the existing economic and social structure and tightened states’ control over fishery labor and catches. The “joint state invasion” culminated in the bilateral fishing agreement in 1957 and a collaborative survey of natural resources in the Gulf. The fact that the centralization of resource control and flows took place almost simultaneously along the Chinese and Vietnamese coasts left the fisherfolk with little leeway to avoid encountering the state. The characteristics of the reform programs and the geographic, technical, and social realities of the locality nevertheless obstructed the political centers’ endeavors to establish primacy along the coastal frontier. This chapter demonstrates that the tensions between internationalist, nationalist, and transnational local agendas were greater at the maritime border than on the borderlands.The defining policies of a communist revolution encountered more determined resistance from the seafaring people whose livelihood relied on an open and integrated maritime space.