August 20, 1939 - the day of the beginning of the defeat on the Khalkhin-Gol River by the Soviet-Mongolian troops of the Japanese aggressors who invaded the territory of the MPR. The book, written on the basis of numerous archival documents, shows the aggressive plans of the Japanese military, Japan's occupation of Manchuria and the creation of a bridgehead of aggression near the Soviet Far Eastern borders, highlights the activities of Japanese intelligence against the Soviet Union, and describes the armed conflict on the Khalkhin Gol River. The publication, illustrated with rare photographs, is designed for a young reader.