It was both. Japan had absorbed over the course of the 20th century a virulent and racialized form of nationalism not entirely unlike European fascism that designated them as superior to other Asian peoples, and demanded that Japan become the natural rulers of inferior races.

But why did that necessarily drive them into the pacific rather than west into continental Asia?

The conquest of Chinese population centers was on the agenda for Japan, but in order to fuel an industrial war effort, Japan needed large amounts of resources like oil and rubber, which aren't found in significant quantities in Japan or much of the Asian mainland, but are plentiful in part of the Pacific like Indonesia, Malaysia, etc. That's why the US oil embargo necessarily set the two powers on a course toward war. If Japan launches an invasion of USSR, they still need the resources from an outside power, and even under the guise of anti-communism, Britain/Netherlands/France/US are going to be skeptical of helping to fuel a Japanese war machine right on the outskirts of their economic colonies in East Asia/South Pacific.

I feel like we already beat the Japanese aspect of this to death over in the Small Conflicts thread.

As for Germany suing for peace, the timing is important. It wasn't at war with the US until after Pearl Harbour. Without a Japanese attack on the US, it is unlikely the US would be formally at war with Germany for some time. The UK and France were at war with Germany over the issue of Poland. Before the defeat of France in 1940, there is no way France was going to agree to peace without Germany (and Russia) pulling out of Poland. Germany actually did make attempts to reach peace with Britain after the fall of France. Despite the British Empire standing alone against Germany in the second half of 1940 and in early 1941, they did not seriously consider agreeing.

For much the same reasons as American "Manifest Destiny" and the Monroe Doctrine tended to keep American attempts at expansionism in the 19th century focused on North and Central America and the Caribbean. It was their own perceived sphere of influence, and it was where the needed resources were most easily obtained.

Also, they had already tried and failed. The Japanese Army, without policy direction from the government, had attempted in the 1930s to expand into Soviet dominated territory. They were decisively defeated by the Red Army a few days after WWII had started in Europe.

In the end, defeating Communism was never a major Japanese war aim. They went to war with the US (and British Empire and the French and Dutch) because these powers were embargoing much needed resources in response to Japanese aggression in China. Obtaining oil, rubber and food by conquest in SE Asia seemed a lot easier for the Japanese than getting it from the Caucasus and the Ukraine.

Apologies if this has been done before. I'm newly venturing into this forum.

Interesting responses. I'm intrigued in particular that much of the discussion on the strategy of Japan (Malaysia, Indonesia, etc) and Germany (Africa, Middle East) bears a strong resemblance to modern discussions... I.e. "It's the oil, stupid"

Well, welcome aboard! The search function wants to be your friend. But to be fair, the "Small Conflicts" thread is hardly the place one would have expected to find discussion about hypothetical coordinated German and Japanese attacks on Russia.

Germany had no strategic objectives regarding oil in Africa or the Middle east. Their involvement in Africa was merely to try to prop up their Italian ally, and protect their southern front from the British. Their limited involvement in the Middle East was mostly targeted at undermining the British. The Germans would have had no practical way to transport Middle Eastern oil to Europe, which is where they needed it.

However, this does not invalidate your point. Strategic considerations were very much about resources, especially oil. The deployment of German armoured divisions between the fall of France and the invasion of Russia was weighted towards protecting from Russian invasion the Romanian oilfields on which Germany was dependent for most of her supply, and the direction of the 1942 German offensive was towards the Russian oilfields.