During World War II, part of the reason that Germany was stopped cold(pun intended) on the Russian front was due to the fact that Stalin was able to move all the Siberian troops that had been defending the coast against a potential Japanese invasion. In fact, 28 divisions had been moved from Eastern Russia to defend Russia at the Battle of Moscow since Stalin knew that Japan could not afford to invade Russia due to their complete involvement with the USA alone.
My question: Could Germany have defeated the Russians and still held off the Western Front had Japan kept its original plan to invade Russia from the East and hold all of their Siberian troops at bay?
Would they have been able to conquer Moscow and defeat Russia if Japan had not become so involved in fight the United States in the Pacific?