The 1951 San Francisco Peace Treaty with Japan left various problems unreso
lved. Japan's territorial problems are no exception. The treaty did not spe
cify to which country Japan renounced its former territories, nor did it de
fine the precise limits of these territories. This article concerns the ori
gin of the disputes between Japan and its neighbors about the "Northern Ter
ritories," Takeshima and Senkaku. Close examination of post-war territorial
disposition of Japan suggests that these problems were seeded under strong
influence of the regional cold war in the Asia-Pacific. Lying on the U.S.
cold war defense line of the Western Pacific, the so-called "Acheson Line,"
these territorial problems were "wedges" to defend Japan from communist ex
pansion. The time shift to the "post-cold war" era does not negate the sign
ificance of the cold war origins of these problems. It seems reasonable to
remember their common origin and consider the possibility of achieving thei
r solutions in a multilateral context.