but interpretation and application of the relevant provisions differ, and the views expressed on them still leave ample room to be unilaterally interpreted and applied. So, it is undeniable that conflicts over ocean waters among the concerned countries are serious and difficult to overcome. To solve these problems, the UNCLOS calls for the countries concerned to make every effort to enter into provisional arrangements of a practical nature. Korea and Japan have maritime boundary problems in the waters surrounding the Korean peninsula, and so, in order to solve those problems, both nations established a joint development zone (JDZ) in the East China Sea in 1974. The zone can be terminated in 2028. Therefore, this study examines and analyzes the impact of the JDZ agreement between Korea and Japan over the East China Sea as to the delimitations of the continental shelf/EEZ

I. Introduction
II. Geological and Geographical Characteristicsof the East China Sea
III. The JDZ under the UNCLOS
IV. The JDZ Cases: Legal and Policy Analyses
    A. China-Japan
    B. Japan-Taiwan
    C. China-Vietnam
V. The JDZ between Korea and Japan
VI. Roles of JDZs for Peaceful Use of Ocean
VII. Conclusion

• Jiajia Wang(Associate Professor at Wuhan University’s China Institute of Boundary and Ocean Studies (CIBOS)) Corresponding Author
• Hyun Soo Kim(Professor of international law at Inha University School of Law, Korea; Guest Professor at Wuhan University)