It seems like China was essentially exploited by foreign powers, including Japan. Japan had been stuck in the middle ages pretty much before the west arrived, but then became a technological and economical giant to be reckoned with.
How did this come to be?
China, in large part, resisted western influence and technology while Japan realized that western technology and certain ideas were superior and adopted them so that they would not be as overtaken by western powers.
Source: HIST 370 Modern China and Japan and I can find the book if necessary.