The open door policy is a concept in foreign relations and economy. As a theory, it originally postulated that the same commercial conditions of thee great powers in China should exist. based on the unequal treaties signed between China and the powers there would be unrestricted access to Chinese commercial markets. This policy originates with British commercial practices, which were reflected in commercial treaties with the Chinese Qing dynasty after the first opium war (1839-1842). Although the open door policy is generally associated with China, it was recognized at the Berlin conference of 1885, which declared that no power could impose preferential tariffs in the Congo Basin.