By 1945, Japan is on the brink of collapse. However, with the bulk of Soviet forces in Europe, the Japanese High Command makes once last desperate gamble for victory and the Kwantung army invades the Russian Far East on 1st April 1945
Taking national seppaku to the next level?
The Japanese High Command had demonstrated a willingness to slaughter its military for no reason at all, so it possible, I guess. Be a bitch to do it on foot, with no aircover (Fuel and aircraft having been almost totally shifted to Kyushu and the Okinawa campaign).
If they tried it, my estimate is that they don't even breach the border defenses in significant numbers. Stalin NEVER really trusted the Japanese & the Far East Front, contrary to popular belief, was never denuded of forces, By 1945, the forces in the Far East had, if anything, been upgraded with newer armor, artillery and aircraft. Since the IJA had dempnstrated that it was incapable of dealing with the 1939 version of the Far Eastern Front this result seems pro-ordained.