In the 19 century, in order to resist the invasion of the western powers in Asia, the Qing dynasty tried to shift the traditional international relationships in Asia to the modern ones with the Qing emperor in the center intactly to maintain the influential status by means of changing the subordinate countries under the tributary system, such as Korea, Vietnam and Ryukyu, to protected states, or merging them, thus promoted to make its subordinate countries protectorates.
19世紀、欧米列強のアジア侵略に対抗するため、清朝は、朝鮮やベトナム、琉球などの冊封国を保護国あるいは併合することによって中国皇帝を中心としたアジアの伝統的な国際関係をそのまま近代的国際関係へと移行させて清の地位と影響力を保持しようとし、冊封国に対して保護国化を強めた。