Japanese View: More than any of the other combatants, Japan’s leadership was a loose coalition of military cliques, fighting over resources with shockingly little thought going to the overall good of the Japanese empire. Each of the major factions had their own ideas on where to go next after a victory at Midway. To oversimplify, there were three major factions competing for resources within Japan:
- The navy. It fought a bitter political battle with army in 1941 over whether to go south, after the western Allies (the navy position) or to go north from Manchuria, after the Soviet Union (favored by one of two major army factions). Historically, after a victory at Midway, the Japanese navy planned to renew their efforts to isolate Australia by pushing down the Solomon island chain, the strategy that historically led to the battles of Guadalcanal. Japanese navy planners projected that isolating Australia would eventually lead to the Japanese occupying Fiji, Samoa and New Caledonia. They might also renew the attempt to take Port Moresby in southern New Guinea that had been aborted by the Battle of Coral Sea. The navy had no serious plans to occupy Hawaii, though harassing the US there from an airbase at Midway was a possibility. There is no reason to believe that they would change those plans after Midway. There is, however, good reason to doubt that the navy’s more ambitious plans to cut off Australia would come to pass. The problem: occupying Fiji or Samoa or New Caledonia would require the army to release more troops to occupy those islands, each of which was defended by a significant number of US troops. The army factions had other uses for those troops, as we’ll see in a bit.
Strategically, the Japanese navy had two main enemies, the western Allies--mainly the US, and the Japanese Army. The navy wanted to maintain their priority access to men and materials, but without a significant US navy to fight for nearly a year, and without a significant role to play in fighting the war until the US built up enough to try to rejoin the Pacific war, the navy was likely to lose some of its access to scarce manpower and raw materials to the army. At the same time, they were dependant on the army to be able to implement their only potential strategy to help win the war. Of the Japanese navy plans, realistically only a renewed attack on Port Moresby and pushing down the Solomon’s chain is likely to happen.
- Japanese army in Manchuria: Historically, in the second half of 1941, the Japanese pursued a dual strategy. They did a massive buildup in Manchuria in preparation for a possible attack on the Soviet Union if the Soviet Union moved significant forces out of Siberia to help fight the Germans. The historic Japanese build-up in Manchuria was massive, more than doubling Japanese forces there to nearly 800,000 men and building up Japanese logistics resources in the area. On August 9, 1941, the Japanese decided not to attack the Soviet Union in 1941, partly because of the US oil embargo, which made it urgent to seize the Dutch East Indies and partly because the Soviets didn’t move significant numbers of troops out of the Soviet Far East until October 1941, too late in the year for a Japanese offensive given the bitterly cold Manchurian winters.
That decision didn’t rule out an attack in the spring or summer of 1942, and the Japanese army in Manchuria continued to build up in the spring and early summer of 1942, with an eye to eventually attacking the Soviet Union. In the summer of 1942 they hit their peak strength, even to the point of forming two armored divisions. For a nation at war, that mass of military power sitting in an inactive theater was an anomaly. It was going to get used somewhere. The Japanese army in Manchuria was eager to take on the Soviet Union, though they probably shouldn’t have been after getting trounced in the 1939 border mini-war at Khalkhyn Gol. They were pushing to go after the Soviets in 1942. Historically, the chances of that happening ended at Midway. The Manchurian buildup gradually reversed starting in later summer 1942, with troops gradually getting pulled into the Pacific to shore up Japanese defenses there. A Japanese victory at Midway meant that the Japanese army in Manchuria still had a chance to prevail and attack the Soviets if the Soviets looked vulnerable. That wasn’t the only possibility though, as we’ll see.
- The Japanese army in China: The Japanese army in China went from being the only war in town to being a backwater when Japan went to war with the Western Allies and built up for a potential attack on the Soviet Union. Historically, in the summer of 1942, the Japanese in China wanted to go back up the priority list. They figured that with only a trickle of western aid reaching Nationalist China, it was time to destroy the Nationalist Chinese once and for all in a massive attack called Operation 5. To do that, they wanted to draw 200,000 men and a lot of logistics from Manchuria. Historically, the tug-of-war between the Japanese army Manchurian and Chinese factions became moot after Midway. Neither faction was going to get to keep those forces, because the Japanese needed them in the Pacific. A Japanese victory at Midway would set up a tug-of-war between the two army factions.