Mekler originally planned to continue onto graduate studies, but he instead attended the
Institute of Oriental Studies of the Russian Academy of Sciences at the recommendation of the
Central Committee of the Communist Party. There, he studied German, English, and Japanese for a year, and received combat training. By the end of 1934, he had the rank of junior lieutenant (). He was then sent as a military
translator to the , and deployed to the
Russian Far East. There, he participated in the
Soviet–Japanese border conflicts. Commander of the Far East Front
Kirill Meretskov tasked Mekler with cooperating closely with Kim, and focusing on improving Kim's domestic image and credibility. According to Mekler, Meretskov told him: He eventually recommended that Kim be the new leader; according to Mekler, he later learned that his recommendation was instrumental in the Soviet's decision to move forward with Kim. Mekler arrived shortly afterwards, and met Kim there. Mekler claims to have arranged and witnessed the first meeting between Kim and
Cho Man-sik at 6 pm on 30 September 1945. Cho has been described as Kim's rival for leadership in the North, and initially had stronger domestic recognition and support than Kim. Thus, Mekler, Kim, and Khan became a consistent trio. In 1946, Mekler was reassigned to a position in
Siberia. Before his departure, Kim asked him for a final piece of advice. He allegedly told Kim the English-language idiom: "
Look before you leap". The two then silently hugged, and Mekler departed. == After North Korea ==