This is another World War II thread, but unlike many of them that proposes some contingency in the course or outcome of a specific battle, this thread concerns itself with a doctrinal difference.
Since the title refers to Tsushima, this quote from Wikipedia seems apropos:
[Tsushima] created a legend that was to haunt Japan's leaders for forty years. A British admiral once said, 'It takes three years to build a ship, but 300 years to build a tradition.' Japan thought that the victory had completed this task in a matter of a few years ... It had all been too easy. Looking at Tōgō's victory over one of the world's great powers convinced some Japanese military men that with more ships, and bigger and better ones, similar victories could be won throughout the Pacific. Perhaps no power could resist the Japanese navy, not even Britain and the United States
Wikipedia: Tsushima
Needless to say, the Mahanian "Kantai Kessen" doctrine failed Japan.
Now, suppose there was some influential "submarine faction" in the Imperial Japanese Navy, and resources instead were allocated towards the construction of submarines instead of the Yamato and Mushashi. Also assume that the IJN's subs would be as good as the Germans.
What if the Japanese deployed more submarines in the Pacific? How would this affect the early battles of the war (assuming that they would occur) such as the Battle of the Coral Sea and Guadalcanal Campaign if the density of submarines increased to patrol and observe the area around Port Moresby and the Solomons?
Although submarines probably require local air superiority (as they cannot stay submerged while traveling for a prolonged amount of time, unlike the U-boat type XXI) in order to prevent enemy aircraft from locating them and interrupting their operations, they could act as reconnaissance (to aid the fleet in locating enemies) and interdict commerce. One reason why the Japanese wanted Guadalcanal and constructed an airfield there was to have a base to interrupt shipping. At best, they could act as area denial in a certain region of the ocean, but unlike
Kessen Kantai, the enemy's fleet would not be destroyed in a decisive battle, but instead be denied from interrupting certain expansionary operations.
Submarine coordination to destroy a significant portion of a fleet would be difficult, especially in the expanse of the Pacific, when compared to destroying convoys as a fleet as a wider range of defenses at its disposal. It would involve radio communication to coordinate attacks against a fleet that may be running anti-submarine patrols with its aircraft and destroyers (and maybe Allied signal intelligence may negate any advanced coordinated tactics would furnish).
Still, I doubt it would affect the outcome of the war of an unconditional surrender of the Japanese because the Allies would just build more destroys and escort carriers. Maybe it would allow enough time for the Soviets to get Hokkaido for themselves.
Maybe I am not asking for history, but a analysis of a war game involving more Japanese submarines in the Coral Sea and the Solomons. And maybe to be educated about the limits of WWII submarine technology and tactics.