Soviet intervention in a collapsing Manchuria

What happens if the Soviet Union attacks Manchuria after blockade pressure begins collapsing Japan's economy?

Britain's response would depend chiefly on the Republic of China's position and whether Britain and China were allied at that point.

Soviet intervention would not automatically become an accepted extension of the anti-Japanese coalition. The Republic of China's wishes would be the first diplomatic variable. Britain's alliance relationship with China would then shape its response. A weakening Japan could therefore expose a new crisis over who controlled liberated or occupied territory in Manchuria.