The Sino-Soviet border in the Far East developed into its present state over a period of more than three centuries. The primary force in the development of this border was Russia's eastward and southward expansion and the filling of a vacuum between China and Russia. This thesis examines that portion of the Sino-Soviet border which delineates the area commonly known as Manchuria. This particular area was selected since it has been the primary focus of conflict involving Tsarist Russia and Imperial China, the Soviet Union and Republican China, the Soviet Union and Japan, and, more recently, the Soviet Union and Communist China. If we except the Soviet offensives in 1945 that ended the Japanese occupation of Manchuria, for example, the greatest conflict was that of Nomonhan in 1939, which was a major armor battle employing corps-size forces. Next in order of intensity was the Changkufeng incident of 1938, which involve division-size forces. The incident-prone nature of these and other localities, including river boundaries, has not been limited to the period of the Japanese occupation. Earlier examples can be cited. It is important to note that the major Soviet invasion routes of 1945 generally passed through the areas of critical incidents. These routes also corresponded with routes featured in Japanese offensive plans as well as in the scheme of fortifications and railroads. The analysis of the border is performed in three major steps. First, terms used in connection with the border are defined, and the border itself is traced briefly. Second, the border is described in terms of the three main geographical frontiers--the western land frontier, the river frontier, and the southeastern land frontier. The development of the border is also traced with reference to significant events such as treaties, military conflicts, and the functions of the boundary. Finally, the military significance of the border is assessed with reference to its development and functions by reference to three main questions. The first of these questions is, "Is the area, or part of it, a cause for armed conflict, or susceptible to incidents leading to armed conflict?" The second, "Is the area of sufficient value to the powers on either side to warrant armed conflict?" The third, "Is the area suitable for military operations, and if so, to what extent?" As a result of the analysis, the most likely trouble spots along the border are isolated. Each of the three sections of the border, of course, has incident-prone areas which have generally served as invasion routes in time of war. The magnitude and intensity of incidents and conflicts along the western and southeastern land boundaries, however, have been greater than those occurring along the river boundary. It is concluded that the most likely trouble-spots along the border are on the two land boundaries, although in the event of all-out conflict, fighting would probably occur in all incident-prone areas isolated in this thesis.

ADA 365172 Approved for public release; Distribution is unlimited. The opinions and conclusions expressed herein are those of the student-authors and do not necessarily represent the views of the U.S. Army Command and General Staff College or any other governmental agency. (References to these studies should include the foregoing statement.)