What is the difference between open-door imperialism and traditional colonial empire building?

Answer 1

open-door imperialism is not so much controlled by the invadeing country, where colonial empire have more demanding control over the colony. also open door have not tarrifs

Answer 2

The issue came up when the great powers dominated China in the late 19th-early 20th century. Each great power carved out a "sphere of influence" in China. Theodore Roosevelt advocated an "open-door" policy, whereby every country could trade with China.