Russia is the only former ally that has not signed a defeat contract agreement with Japan since World War II, and its country is still in a state of war against Japan legally. What's more, in recent years, with its strong military strength, Russia has constantly put pressure on Japan, which has made Japan very embarrassed.
At the beginning of the 20th century and during World War II, Japan had two important military contests with Russia and the Soviet Union. During the Russo-Japanese War, Japan seized huge benefits in the northeast of China, and the Nomenkan campaign decided that Japan would abandon its northward movement and choose the southward strategy. The Russo-Japanese War was a contest of national strength between Japan and Russia at that time. After the Sino-Japanese War of 1894-1895, Japan was strong and eager to invade and expand abroad.
At this time, Russia is on the eve of the Great Revolution, making many enemies in Europe, and the whole country is on the eve of collapse, so it is not surprising that Japan won the Russo-Japanese War. Russia is a feudal imperialist country that opposes industrialization more than Japan. The Russo-Japanese War took place between 1904 and 1905, and Russia did not abolish serfdom until 186 1 year.