[quote="SamH, post:19, topic:176406"]
The "decisive battle" that Japan wanted so badly would have gone poorly for them had it been fought in early 1943. At that point the US had 6 new battleships - any one of which was near equal to any two Japan had except for the Yamato and Musashi. Most of Japan's battleships were well over 20 years old and would have faired as poorly in a sea battle at long range as the old US battleships faired in Pearl Harbor. Of the existing battleships the US had in December 1941 most likely only the Colorado Class might have been included as "first class” ships of line. The rest of the US battle fleet was too old and dilapidated to have even sailed to a far battle in the Pacific without first being overhauled.
A sea battle with carriers would have gone equally as poor for Japan. In early 1943 the US could have had 9 fully worked up large carriers armed with planes (F6F) that could match or better the Zero. At that time Japan would have only had 8 large carriers and 4 small carriers - and most of their large carriers were older "conversion" ships with questionable damage control and ability to withstand hits. Where as all 9 of the US carriers could launch over 80 planes, only 3 (?) of the Japans carriers were able to match that number.
Well, in the scenario I just outlined (with Japan sparing the battleship fleet at Pearl), it wouldn't be a "decisive" battle in the sense in which Japan spoke, that of ending the war, of course.
My point is, in this scenario, the US fleet, had it tried to strike back as soon as its fuel problems were solved, would have been going up against an enemy skilled in carrier tactics already, whereas the American commanders would probably still be thinking in "battleshipcentric" terms, with the carrier commanders not being overly-experienced yet, and the carriers not taking an actively offensive role.
Even if the American commanders had been imaginative and innovative enough to switch tactics mid-stream and fight effectively with carriers, the balance might still have been tipped in Japan's favor by long-range land-based bombers flying from newly-fortified islands in Japan's eastern island perimeter.
And if the US had committed the whole fleet to such an action, they might well have had to rebuild it all from scratch, giving Japan the luxury of yet another year or two in which to further fortify its perimeter, even if steel shortages meant they couldn't replace all their own shipping losses.
The battle might have been crucial (a better word than "decisive")l in affording Japan the opportunity to reach a "critical mass" in terms of building airstrips, stockpiling fuel, and deploying bombers on its perimeter capable of projecting heavy air power at any invading fleet, perhaps to the extent of compensating for all its naval losses, in any conventional offensive operation.
If, as you say, America would not have tried to send its battleships that far west, the net effect would still be one of giving Japan time and space to fortify its perimeter.
Japan's strategists may have thought of all this, and just hoped Americans would eventually tire of war and wouldn't have the stomach to rack up all the casualties that dismantling that perimeter would entail. They might even have been right about that--after all, people were calling for investigations after the Tarawa battle, in which less than two thousand Americans perished. Americans don't like huge casualty numbers, and certainly wouldn't have tolerated the numbers Japan or Germany or the USSR suffered.