There is some debate over the “legality” of the USSR break with Japan regarding their Non-Aggression Pact. The Pact called for an automatic renewal, the Soviet declaration was a notice of non-renewal. The interpretation given here is that a party to the Pact needed to give notice of non-renewal “in the year before expiration.” However, another interpretation (which was the Japanese interpretation) says the Pact stated notice was to be given “one year before it’s expiration.”
Under the Soviet interpretation, as given in the Times, the notice was properly given in year four of the Pact and the declaration of war in August was not a violation. The Japanese interpretation, which was understandably not given, would have given a one-year grace period from notice to hostilities.
In any event, the Soviet declaration of non-renewal should have made it quite clear to the Japanese that a deal had been cut at Yalta for the USSR to come into the war against them, not long after the defeat of Hitler’s Germany. That defeat looks to be only a few weeks off at best. Why the Japanese thought the Soviets would act as “honest brokers” for a peace deal in June and July is baffling to say the least. Denial is more than a river in Egypt, it appears to have been an integral part of Japanese culture.
Stalin knows the war is over. He is in the land grab stage - determined to grab as much land as he can before hostilities end. Manchuria looks tempting . . .