Answer: spheres of influence
In international relations, a sphere of influence is a region over which a state has a level of cultural, economic, military or political control. This control is exclusive and more accommodating to the power outside the border.
China in the late 19th and 20th century was divided into these spheres of influence, as many European powers held control over large territories. These were taken either by military attacks, threats to the Chinese authorities or unequal treaties.