the 1930s, many ethnic Koreans in the region joined and participated in the Chinese Communist Party. In December 1938, a counterinsurgency unit called the Gando Special Force was organized by the Japanese Kwantung Army to combat communist guerrillas within the region. The top commander of this battalion-size force was Japanese. Historian Philip Jowett noted that during the Japanese occupation of Manchuria, the Gando Special Force had "earned a reputation for brutality and was reported to have laid waste to large areas which came under its rule." On 1 October 1943, Jiandao Province was incorporated as a district into the Dongman Consolidated Province but this district was itself abolished on 28 May 1945 and Jiandao was once again a province. After World War II and the liberation of Korea, many Korean expatriates in the region moved back to Korea, but a significant number still remained in Manchuria; descendants of these people form much of the Korean ethnic minority in China today. The area was first nominally part of the Republic of China's new Songjiang Province but with the communist seizure of power in 1949, Sonjiang's borders were changed and Jiandao became part of Jilin Province. The area is now the Yanbian Korean Autonomous Prefecture in Jilin. Boundary claims The claims by some of the Korean irredentists over Gando stem from what is perceived as an ambiguity in the original Sino-Korean boundary agreement. After several attempts by the Kangxi Emperor to negotiate the issue, in 1712, the Joseon of Korea and Qing of China agreed to delineate the boundaries of the two countries at the Yalu and Tumen Rivers. The Qing delegation was led by Mukedeng, and the Joseon delegation was led by Pak Kwon, and the two held a joint commission to survey and demarcate the boundaries between the two states. Efforts were taken to locate the sources of the Yalu and Tumen rivers at Baekdu Mountain. Owing to Pak's age, they agreed for Mukedeng's team to ascend the summit alone. Mukedeng's team quickly identified the source of the Yalu, but identification for the Tumen proved more complicated. At last a spot was decided, and a stele was erected as a boundary marker. Over the next year, a fence was built to demarcate the areas where the Tumen river ran underground. Pak Kwon was instructed by the Joseon government to retain all territory south of the Yalu and Tumen rivers, a