What if once it became clear that the Soviets are going to win the Russian civil war, the Japanese just annexed the rest of Karafuto? What impact would this have on history? I have often read on here that the Japanese felt betrayed that they weren't allowed to annex the whole island back in the Russo-Japanese war and that it was this what brought them on the expansionist path. Would the Japanese still partake in WW2 on the Axis side? If yes, how does Japan owning the resource rich northern half affect the war? According to the CIA, northern Sakhalin produced 1,750,000 tons (almost 12mil barrel) of oil in the 1941-45 period. Will the Japanese use that oil to mechanize their army? Assuming WW2 plays out much like IOTL, what would happen to Karafuto once Japan loses? IOTL the Americans objected the Soviet invasion of Karafuto, will we see more effort to try to not let the Soviets invade it? Could Karafuto be part of modern day Japan?