<P> In more extreme cases, a country within the "sphere of influence" of another may become a subsidiary of that state and serve in effect as a satellite state or de facto colony . The system of spheres of influence by which powerful nations intervene in the affairs of others continues to the present . It is often analyzed in terms of superpowers, great powers, and / or middle powers . </P> <P> An example of spheres of influence was China in the late 19th and early 20th Century, when Britain, France, Germany, and Russia (later replaced by Japan) had de facto control over large swaths of territory . These were taken by unequal treaties or as very long term "leases". These powers (and the United States) might have their own courts, post offices, commercial institutions, railroads, and gunboats in what was on paper Chinese territory . However, the foreign powers and their influence in some cases could have been exaggerated . The system ended with the Second World War . </P> <P> For another example, during the height of its existence in World War II, the Japanese Empire had quite a large sphere of influence . The Japanese government directly governed events in Korea, Vietnam, Taiwan, and parts of China . The "Greater East Asia Co-Prosperity Sphere" could thus be quite easily drawn on a map of the Pacific Ocean as a large "bubble" surrounding the islands of Japan and the Asian and Pacific nations it controlled . </P> <P> Sometimes portions of a single country can fall into two distinct spheres of influence . In the colonial era the buffer states of Iran and Thailand, lying between the empires of Britain / Russia and Britain / France respectively, were divided between the spheres of influence of the imperial powers . Likewise, after World War II, Germany was divided into four occupation zones, which later consolidated into West Germany and East Germany, the former a member of NATO and the latter a member of the Warsaw Pact . </P>

Japan's sphere of influence was in what region
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