On August 15, 1945, at the end of World War II, U.S. President Harry S. Truman, in His General Order No. 1 to the Soviet Union (the order to Japan on the details of surrender), informed him of the main points and contents of the liquidation, which was the distribution of countries after Japan's surrender, that is, the distribution of areas actually occupied by countries.
Among them, the Soviet Union was assigned to Manchuria, the Korean Peninsula north of the 38th parallel north, and the southern Sakhalin Islands, excluding the Kuril Islands. In this regard, Stalin wrote in a letter to Truman on the 16th that the Japanese army surrendered, and the Soviet Union should acquire all the islands of the Kuril Islands based on the secret treaty of the Yalta Agreement, and also proposed a new request for obtaining the northern half of Hokkaido north of the connection between Kushiro City and Rumon City, hoping that the United States would support its reasonable demand. Why did Stalin demand the occupation of the area north of the Rumon-Kushiro Road?
Why did the Soviet Union covet Hokkaido in Japan? Four reasons can not be ignored, look at the map will understand, the two cities mentioned above have a common point, that is, they have a large port, both contain rich coal and iron ore resources. Although Rumon is now a quiet port city, it was at the time second only to Otaru and Wakkanai on the coast of the Sea of Japan in Hokkaido.
During the Russo-Japanese War, the port was already large enough for Japanese troops to travel to the Liaodong Peninsula in China, and it was also a transportation point connecting Naruchi in the north of the province, Abashiri in the east of the province, and Sapporo in the middle of the road. In addition, at that time, the surrounding area of Liumeng was a coal mine gathering place, and it was not difficult to imagine the busy scene of transporting coal from here to various places.
The main areas of the Urals of the USSR were abandoned during the war, and coal as an energy source was important in the context of national reconstruction. Japan is also facing a revival after the war, and it also attaches great importance to the coal industry. It was important to have a port next to the coal mine to transport the accumulated coal out, and there were many coal mines and labor north of the Liumeng Yijun Route.
Even more striking than the energy base is the introduction of German technology to create man-made oil. Of course, the technicians and related documents were obtained from the Germans, and it is not known whether the research facilities were destroyed by the war, but the research institute is still there.
Food is also very important. Hokkaido, which is warmer than Siberia, has agriculture centered on butcher farmers. The Sea of Okhotsk is one of the world's three major fishing grounds and can serve as an energy and food supply base for the Soviet Far East. With energy and food support, self-sufficiency in the occupied areas would be possible.
In addition, it is more meaningful that if this line of support can be guaranteed, it will not only make the Hodsk Sea the inland sea of the Soviet Union, but also realize the dream of Having an ice-free kushiro port in the outer ocean that Russia has been pursuing since the beginning of the imperial era. From here, submarine forces can be sent directly into the Pacific. For Stalin, the establishment of aviation bases in northern Hokkaido and the Kuril Islands and South Sakhalin Islands could effectively protect the security of the Soviet mainland.
If the north of Rumo-Kushiro had been occupied by the Soviet Union, the division of Hokkaido would have become a reality, and The Sagawa River, which would connect Rumo-Asahikawa and Sapporo, would have become an occupied area of the Soviet Union, and Rumo-Kushiro would no longer be a fishing port, but would become a military port and supply base for the Japanese army deployed on the hokkaido dividing line, which would be very different from the current situation.
In response to Stalin's proposal on August 18, Truman responded: 1. Agreed to the Soviet occupation of all areas of the Kuril Islands; 2. Refused the Soviet Occupation of northern Hokkaido; and 3. Demanded the establishment of a US air base in the Kuril Islands. But this demand was not immediately met with a Soviet response. At Stalin's behest, The Soviet Chief of Staff Antenov ordered the Soviets to continue fighting on the grounds that "Japan has not issued an armistice order and the Japanese army is still engaged in continuous resistance."
In order to carry out the plan to occupy northern Hokkaido, Vasilevsky prepared two infantry divisions and related naval and air support, but unfortunately, the plan was eventually cancelled due to strong opposition from the United States.