3: The tension between Japan and Germany. I was surprised to see this depicted. I do remember one source discussing that Japan planned an immediate offensive into the Soviet Far East if it looked like Russia was going to fall. The main objective was to take as much territory as possible in order to keep Germany as far away as possible from mainland Japan. That plan did show that while they were Allies, there was a concern in Japan that Germany would start to ‘overshadow’ their influence in Asia if Germany was able to defeat the Allies. While Germany and Japan were Allies, they did not cooperate that much, and only had limited transfers of technology, information or material. While never really made clear, it seemed that Germany did not want to give Japan access to the technology that it had, which it could have easily done prior to the start of the war with Russia in 1941, and still done into 1942 with long range flights from forward airbases bases in the Soviet Union.
There was also no coordination on grand strategy. Germany was never able to get Japan to attack Russia in 1941, and this allowed Russia to transfer its Siberian army to defend Moscow and launch the winter offensive that did a lot of damage to the German forces in front of Moscow.
Japan never seems to have shared with Germany that it was about to bring the United States into the war December 1941 or what would happen next if the United States was now in the war. There was also the possibility that the United States would have been only at war with Japan if Germany did not declare war on the United States.In that situation, Germany could have done a lot better against Britain and Russia, since there would have been no United States forces in that theater, but Japan would have done a lot worse since most of the United States forces would have been available to be deployed against Japan only.
On a grand strategic level, I think one of the biggest mistakes for the Axis was bringing the United States into the war. If Japan had not done the attack at Pearl Harbor, and had either attacked Russia or, in the alternative, just did an offensive in Southeast Asia and Pacific against Britain, French areas, Dutch areas, but left United States and Philippines alone; it is possible that the United States would have not entered the war until much later and Japan had already consolidated its conquests.
