Throughout history, physical terrain, political fiat, and conquest have divided states into separate political entities just as much as race, ethnicity, language, and religion. One result is man-made and sometimes arbitrary or even imposed boundaries. Compared to other kinds of cross-border areas, internationally disputed areas are always characterized by undemarcated boundaries as well as political and institutional uncertainties. Boundary and territorial disputes refer to disputes over the division of land or water bodies among two or more independent countries. Boundary disputes may evolve from historical and/or cultural claims, or they may be brought on by competition for resource exploitation. Ethnic clashes continue to be responsible for much of the territorial fragmentation around the world. Disputes over islands at sea or in rivers frequently form the source of territorial and boundary conflicts. Other sources of contention include access to water and mineral resources (especially petroleum), fisheries, and arable land. Issues pertaining to the territorial control of seawaters have long been the subject of international law.
Boundary and territorial disputes are often the result of divergent material claims, especially regarding land, freshwater, and mineral and energy resources. This has particularly been the case in the international context, where sovereign control within one’s territorial boundaries is thought to be a defining characteristic of a state (Wendt, 1999, pp. 201–14). Thus, reasonable disagreements over determining boundaries, where one entity’s control begins and another ends, may lead to open violence. Although there are some generally accepted rules of boundary demarcation and extension of a state’s territorial sea limits, emphasis on potential underground and undersea resources has generated a number of inter-state disputes around the globe. In the coming decades, as a result of growing energy demand, it can be seen that undersea oil/gas exploration will become more contentious.
In cross-border areas, especially disputed areas, natural and human systems usually interact under conditions of uncertain, imperfect information and, in certain circumstances, human actions on one side of a border can have irreversible effects on resources and environment on the other side. As a result, even a tiny disputed area could become the source of a large, regional and international clash. Disputed areas usually have been the most important topics in cross-border and area studies. Also, they have been one of the major obstacles for developing and transitional nations with differing economic, political and cultural systems and different capacities for implementing sustainable development strategies (Guo and Yang, 2003). Boundary and territorial disputes vary in intensity from managed or dormant to violent or militarized. Sometimes, conflicts may arise when national interests differ and nations develop diverging policies and plans which are not compatible. In all cases, nations wishing to exploit the resources at their marginal territories need to precisely identify their international boundaries and to be able to peacefully resolve territorial disputes as well as to cooperatively manage cross-border resources with their neighbors.
This paper sets out to analyze the critical analytical and policy issues relating to maritime boundary disputes and undersea hydrocarbon exploitation in the East China Sea. In Section 2, I will address such question as why China and Japan have found it so difficult to cooperate. To this end, various domestic and external factors that either promote or prevent the joint/cooperative development of the East China Sea are examined. Section 3 defines some principles and rules of cross-border petroleum exploitation and, after reviewing existing international agreements and treaties relating to seabed oil/gas exploitation in various disputed areas throughout the world, constructs five joint/cooperative development models (solo development, parallel development, joint venture, joint authority, and trustee development). In Section 4, according to the spatial cost-benefit analysis of seabed oil/gas operations, the appropriate development models are suggested for the various zones of the East China Sea. Also, the political and economic feasibilities of moving the current bilateral structure (China-Japan) of joint hydrocarbon exploitation to a trilateral structure (China-Japan-Taiwan) are assessed. Finally, this paper concludes with some policy suggestions for China and Japan in their approaches to the resources under the East China Sea.
 A typical example is for uppermost riparian countries to over-exploit the waters flowing through its territory, which could affect countries downstream (Guo, 2005, pp. 55-6).
 See, for example, Kirmani (1990), Frey (1993), Wolf (1998), and Savenije and van der Zaag (2000).