open door policy

in the late 1800s, each of the great powers of europe – great britain, germany, france, and russia — was eager to increase business opportunities in china, the world's most populous nation and a potentially huge market for trade in order to avoid conflict, the european leaders agreed to carve the country into "spheres of influence”-specific geographic regions, or spheres, of china in which each nation controlled trade.

secretary of state john hay, concerned that u.s. merchants might be shut out, sent a series of "open door notes" to the european powers in 1899 and 1900, asking them to respect china's territory and independence. the leaders agreed to america's open door policy to avoid a confrontation. china opposed the policy because the foreign influence was considered excessive. it led to the boxer rebellion of 1900, which the u.s. later helped suppress.