Scholars of the Soviet Great Purges and the Siberian gulag (i.e., prison camp) system it produced have tended to emphasize only domestic factors that may have led to the Stalinist purges. But one highly coincidental foreign policy factor that deserves special attention was Tokyo's 1936 announcement that it intended to sponsor and pay for the trans-shipment of over 5 million Japanese immigrants to its puppet state of Manchukuo, which bordered on the USSR's Far Eastern territories. Even though Japan never even got close to carrying out this policy, since its program was voluntary only, by the end of World War II some five million transported European Russians were living in Siberia, many of them located right north of the Soviet border with Manchuria (see Map 4).

The history of Japanese immigration to Manchuria dates back to Japan's victory in the 1904–1905 Russo-Japanese war, when Japan obtained the southern branch of the Chinese Eastern Railway, which was renamed the South Manchuria Railway (SMR). In addition to the 170,000 Japanese who eventually worked directly for the SMR, thousands of other Japanese immigrants flocked to Manchuria during the following decades. According to Yosuke Matsuoka, the president of the SMR during the 1930s as well as Japan's foreign minister during World War II, Japanese immigration to Manchuria was considered to be the first line of defense against Russia, since the “leaders of Japan […] suspected that defeated though she was, Czarist Russia would sooner or later strike back at the island Empire in revenge.” Thus, the Japanese government decided that in Manchuria “encouragement might be offered for the settlement of as many Japanese as possible in the new land and for the launching of all sorts of enterprises by such settlers […] indispensable to the protection of Japan's life-line of the Asiatic continent.”