enemy. Compounding the problem, the Japanese military made many wrong assumptions and major mistakes, the two most significant the following: They wrongly assumed that any attack coming from the west would follow either the old rail line to Hailar or head into Solun from the eastern tip of Mongolia. The Soviets attacked along those routes, but their main attack from the west went through the supposedly-impassable Greater Khingan range south of Solun and into the center of Manchuria. Japanese military intelligence failed to determine the nature, location, and scale of the Soviet buildup in the Far East. Based on initial underestimates of Soviet strength and the monitoring of Soviet traffic on the Trans-Siberian Railway, the Japanese believed that the Soviets would not have sufficient forces in place before the end of August and that an attack was most likely in the autumn of 1945 or the spring of 1946. The withdrawal of the Kwantung Army's elite forces for redeployment into the Pacific Theatre made new operational plans for the defence of Manchuria against a seemingly-inevitable Soviet attack prepared by the Japanese in the summer of 1945. They called for the redeployment of most forces from the border areas, which were to be held lightly with delaying actions. The main force was to hold the southeastern corner in strength to defend Korea from attack. Furthermore, the Japanese had observed Soviet activity only on the Trans-Siberian Railway and along the East Manchurian front and so prepared for an invasion from the east. They believed that when an attack occurred from the west, their redeployed forces would be able to deal with it. Although the redeployment had been initiated, it was not supposed to be completed until September and so the Kwantung Army was in the process of redeployment when the Soviets launched their attack simultaneously on all three fronts. Campaign The operation was carried out as a classic double pincer movement over an area the size of Western Europe. In the western pincer, the Red Army advanced over the deserts and mountains from Mongolia, far from their resupply railways. That confounded the Japanese military analysis of Soviet logistics, and the defenders were caught by surprise in unfortified positions. The Kwantung Army commanders, involved in a planning exercise at the time of the invasion, were away from their forces for the first 18 hours of conflict. Communication infrastructure was poor, and communication was