After the Russian Revolution of 1917, the Soviet Union was regarded as a major threat to Japan's security, and the army felt it needed Manchuria and whatever other Chinese territory it could control as a buffer against Russian advances.
The Japanese army did not see the Russian Revolution as an important event.
mnli hypothesis: The Japanese army did not see the Russian Revolution as an important event. premise: After the Russian Revolution of 1917, the Soviet Union was regarded as a major threat to Japan's security, and the army felt it needed Manchuria and whatever other Chinese territory it could control as a buffer against Russian advances.