Korean Peninsula locates in the Northeast Eurasia, adjacent to China. China and Korea are friendly neighbors and Korea has maintained close interactions with China since ancient timesFrom the end the 16th Century and the beginning of the 17th Century, Ming Dynasty started to decline gradually while Jurchens developed rapidly under the leadership of Nurhachi and founded the Later Jin Dynasty. Later Jin Regime and Ming Regime had long fought a battle since the foundation of the Later Jin Regime. Korea gradually changed its policies with Ming and Later Jin according to the changes of the international situation. At that time the international situation was extremely complicated. The interactions between the two countries using different languages can only be accomplished with the help of those who knew Jurchen language well. They are called Tongsa or interpreters. The most fundamental way to become a Tongsa or an interpreter is to pass the translational exams to enter the Translation Department. When there were tasks to carry out, the suitable candidates will be chosen from the department and appointed as Tongsa to serve the envoy abroad.The Jurchen Tongsas not only served as interpreters but also conducted trading activities indirectly. Tongsas were merchants acknowledged by the government. They not only sold the stuffs they carried but also worked as trading agencies. Except the Jurchen Tongsa in Korea, there were similar positions in Later Jin (Qing) as well. They were also Korean, who were captured by the Later Jin in the battles between Korea and Later Jin and then paid allegiance to Later Jin. They gained the trust from the governors of Later Jin by their advantageous language proficiency. They were called Tongsaguan and often served as envoys in the diplomatic missions withKorea.They also ganged up with Korean Tongsa with their exceptional advantages, forming a clique to pursue selfish interest such as taking bribes.