World War II involved two almost totally distinct theatres - Europe and the Pacific.
On the Allies side, most of the same players were involved in both theatres (although the French and Dutch possessions were pretty much wiped out, and they didn’t do much to help reclaim them) and there was significant co-operation, including join operations.
Apart from sharing information (which arguably helped the allies more than the Axis partners) did Germany and Japan ever have an opportunity to co-operate during the war?
More generally, if it is assumed that they were both going to war anyway for their separate reasons at around the same time, did the formal alliance aid either party?
(Looking for GQ information here, not opinion about political effect on the USA entering the European theatre).
There was a lot of info sharing but little else. They were simply too far away. There were a few issues too.
Ironically Vichy France had made a “peace” of sorts with Germany and was legally in charge of places like French Indochina, and this made a strain for Germany as as helpless as Vichy France was it was still more reliable than Spain and tougher than Italy.
Germany was no match for Britians Navy so there was no way troops could be sent.
All Japan could do was to attack Siberia. And so what? Japan was having trouble holding anything but the coast and a hundred miles inland from that in China. If Japan had attacked the Soviets all the Soviet Union had to do was fall back to a safe point and let the Japanese freeze. This is what they did to the Germans on the East. Japan knew this and knew there was no point to invading Siberia a big hunk of cold. Even though it has resources you still have to be able to get them out. Even today Siberia has very limited transportation.
The Soviet Union was too big and Japan was way overextended even in the best of times.
The Japanese plan for WWII seemed to be to overextend way too much then when the Allies beat Germany they’d be too tired to fight on, then Japan, which grabbed as much territory as it could, could give bits and pieces back as bargaining chips.
Japan was and still is very short of natural resources so it’s Navy was vital and after the Battle of Midway, Japan had to concentrate all time making sure the oil from the Dutch East Indies (Now Indonesia) could be kept flowing.
It wasn’t cooperation but the Japanese had border skirmishes with Russia that culminated in:
The Battle of Khalkhyn Gol(Mongolian: Халхын голын байлдаан; Russian: бои на реке Халхин-Гол; Japanese: ノモンハン事件 Nomonhan jiken–i.e. Nomonhan Incident) was the decisive engagement of the undeclared Soviet-Japanese Border War, or Japanese-Soviet War, fought between the Soviet Union, Mongolia and the Empire of Japan in 1939. The battle was named after the river Khalkhyn Gol passing through the battlefield. In Japan, the battle was known as the Nomonhan Incident after a nearby village on the border between Mongolia and Manchuria. The battle resulted in total defeat of Japanese 6th army.
About the only battle where both Axis and Allies took part was Madagascar where the British faced the Vichy French and two Japanese midget subs took part and badly damaged HMS Ramillies
Germany sent a submarine with Uranium to Japan to help their atomic program; if it hadn’t surrendered, who knows if things might have turned out different?
The uranium shipment constanze cites was just one of the final examples of a long standing cooperative arrangement between Germany and Japan shipping strategic materials (e.g., tin, nickle, rubber, quinine) and specialized technological knowledge (e.g, German aircraft blueprints) between the two nations, post-Pearl Harbor most often by submarine. While Japan apparently purchased a Tiger tank from Germany (and was seriously price-gouged), submarine transport proved impractical and it was never delivered.
There was also an an only marginally successful effort to establish a base for U-boats at Singapore to operate in the Indian ocean. Much of this limited naval cooperation is detailed here.
An Italian aircraft flew from German-occupied Russia to Japanese-occupied China in 1942 to deliver diplomatic code books. I couldn’t find much about this flight on-line beyond this mention, but I read a fairly extensive article about it years ago, possibly in the US Naval Institute’s Naval History magazine.
But clearly there was no meaningful strategic-level coordination between Germany and Japan. The hope of each “ally” that the other would tie down its enemies on the other side of the world was about the only high-level impetus for the alliance.
One good thing about this co-operation (from the Allies point of view) was the regular reports that the Japanese Ambassador in Berlin radioed back to Tokyo concerning the German war effort. Japanese diplomatic codes had been broken very early in the war, so the content of these reports proved very useful to the Allies.
I have heard that the way the US entered the war was (1) Japan attacked Pearl Horbor, (2) US declared war on Japan, (3) Germany declared war on the US, (4) US declared war on Germany. The rest, as they say, is history. But I have long wondered what would have happened if Germany hadn’t declared war on the US. Yes, the US would have mopped up the Japanese as they did in the end anyway. But wouldn’t Germany have won the war in Europe?
I know Germany was obligated by treaty to attack the US, but treaty obligations didn’t stop them from attacking The Soviet Union. Which leads to another hypothetical, but that one is too far off the topic.
There have been threads here on the “What if Germany hadn’t declared war” issue before. The main thing to keep in mind is that the US and Germany had effectively been fighting an undeclared naval war in the North Atlantic throughout 1941. Even without a Pearl Harbor, the US would likely have declared war on Germany before 1942 was out. While there might have been more organized political opposition to such a war (and there were those historically who continued to feel that the war in Europe didn’t need to be a US concern – Heck, Pat Buchanan still thinks so), public opinion had been drifting in that direction for some time. Once the US and Japan were at war, the momentum would have built even more rapidly.
It probably wasn’t, actually. The Tripartite Pact stated that “[Japan, Germany, and Italy] further undertake to assist one another with all political, economic and military means if one of the Contracting Powers is attacked by a Power at present not involved in the European War or in the Japanese-Chinese conflict”. Since Japan attacked the United States, not the other way around, Hitler would have probably been within his rights under the treaty to tell the Japanese they were on their own and would have to get themselves out of the mess they’d just managed to get themselves into. As you point out, Hitler wasn’t really all that big on the fine print of treaties (or, in the case of the Molotov-Ribbentrop Pact, the large print), and went ahead and declared way on the USA anyway, as did his junior partner, Mussolini.