First, Korea did not colonize China. Korea and parts of China were colonized by Japan. Most Koreans opposed the expansion of Japan into the Korean peninsula and the expansion … into Manchuria (China). Unfortunately, few of them could express that will in any tangible way.here are a few reasons why Japan colonized Korea:    1) Raw Materials: Japan was a country that was formed by  volcanic eruptions, which means that it has almost no m … etal, coal,  petroleum, or other deposits that are requisite for  industrialization.