Nature of the alliance between Japan and Germany in WW2

[ReluctantSamurai]

Not exactly. The Japanese leadership were angered because they were not provided the exact date and time of the attack. IIRC, Prime Minister Konoe felt betrayed because the Germans did not trust them enough to warn them ahead of time.

While Japan might have had an inclination to believe that Germany was going to invade the SU, the general consensus in the Japanese AGS was that the information coming from sources in Germany were nothing but misinformation. News of the attack came from press releases and caused Konoe to consider, for a brief time, withdrawing from the Tripartite.

The biggest opportunity for cooperation would surely have been a combined attack on the Soviet Union. Hitler always hoped for such a situation, and did all that he could to make it happen, including declaring war on the United States with the expectation of reciprocation.

Nothing truer could be said than the first sentence. It was indeed the best opportunity for Germany and Japan to actually have some sort of working relationship. But the rest of that statement is rather puzzling. If Hitler wanted active Japanese co-operation, surely he would have let them in on his plans? Or at least given some notification of H-hour? And Germany's declaration of war on the United States had nothing to do with the attack on the SU, and in fact could be considered counterproductive to Barbarossa because it now qualified the SU to begin receiving LL aid.

However, Berlin made it well known to the Japanese that the Germans were going to attack the Soviet Union. Hitler courted the Japanese for nearly a year before the invasion, hoping to get a commitment.

Could you expand a bit on how this was done?