ORIGINAL: witpqs
As far as what Japan could have done with a better strategy, they did not have the technology that the Allies had in the Atlantic vs Germany. There were other aspects of the situation different IRL too, of course, but in a game exploring what-if you could argue about which what-ifs to allow or not. They clearly could have done better with a different strategy, although it is a what-if in terms of what strategy they could have achieved given their internal politics and other factors.
Here is where I wish Symon were still around.
The Pacific's geometry is wholly different than the Atlantic's ASW-wise. In the Atlantic there was a mid-ocean gap that could not be covered from the Azores, et al in the critical phase of the BOTA; jeep carriers were developed for this in part. But as I said the Atlantic was pretty much a straight-line, point-to-point convoy problem. The Allies used mass and mass escorts to ram the convoys through. The Germans used mass and wolfpacks and shore direction to try to maximize their assets against this relatively simple ( versus the PTO) model.
The Japanese had a radically different problem. Distances vast compared to the Atlantic. Not point-to-point on the production side, but highly atomized. Not even hub & spoke to the garrisons. No one with a straight face would claim they had the capacity at any level to field a large force of CVEs to take air cover along on the trip to the Marshalls or Marianas. Whatever ASW they were going to have had to go along in the form of surface ships.
But they didn't have those either in the quantity, and most importantly form, they needed. What did they need? Not converted fishing boats or light 10-12 knot merchants (we see in game too.) Why? As I said before, the night end-around attack. A USN fleet boat at flank in a low sea state could do 20-knots on the surface for days. With surface search radar from mid-1942 onward. The geometry is simple. Detect, move to 10-ish NM, track, and run forward along the track to attack position. Wait there off the track for the convoy to amble along. Hours to chart the zig system and prepare. At the sub's choice of time and place attack on the surface, running in at flank to 1500 yards or so--3/4 mile in pitch darkness--to shoot, and then evade on the surface, possibly diving in mid-evasion if there were multiple escorts in cooperative positions. Many of the damage reports I linked to came during this post-attack evasion, submerged. Some of that we see in the game too, but often the attack was on the converted merchant acting as a PB and not the fat xAKs it was escorting.
To defend the night end-around an escort force needs several things. 1) Speed in excess of 20 knots. 2) Working radar operated by trained men 3) A cooperative doctrine among escorts present to guard both sides of the track as well as a system to assign "chasers" and "herders" after it is clear a sub is present and hunting. Japan never developed any of these.
A 20-plus-kt. escort in the era was pretty hard. Reciprocating engines could get to 20-kts--subs had diesels--but they were not off-the-shelf chuggers. The USN had tremendous problems getting its sub diesels "there", and one class of wartime sub never did get its engines really working. Japan did not have the industry to rapidly crank out those engines with so many other forces in their defense establishment vying for the resources. The only alternative to diesels would be turbines, which is an order of magnitude more difficult, expensive, and training-intense in a small ASW corvette or patrol frigate.
Radar? In those quantities and designed to work in a vessel that small, with a high AC power need, a highly-placed mast that added stability concerns, and again, trained men to operate and repair at sea was beyond Japan's capacity. If they had only needed to escort to 5-6 ports they could have made it work by using real DDs. But in 1942-44 they needed to go to hundreds of locations on the outbound side. I have in the past posted links to post-war Allied technical analysis of IJN electronics, primarily sonars. They were primitive by comparison to ours, and that was in 1945. To design, build, and maintain with training and spare parts several hundred new radars would have been infeasible.
Training? Seemingly the easiest of the three issues I listed, but still very difficult. The Japanese war machine struggled to find enough recruits with basic mechanical knowledge to fix tanks and trucks. There wasn't a big, domestic pool of teens with electronic or even electrical basics. But if they had found the engines, built the hulls, produced the radars they might have been able to get over the training hump. Might.
I know I sound like a broken record on the sub war in the game. But it's not like quibbling over drop tanks. The sub campaign was a tent-pole of the Allied effort. On balance it was more important to winning than anything carriers did, as radical an idea as that is around here. I have always assumed GG and the Originals nerfed it either because they didn't understand it, or more likely because it was so devastating and few players would tackle Japan if it were true. And I don't wish it were true. I just wish it were closer. A lot of players come here saying they "don't know much about the Pacific war." After playing AE they think it was necessary for the USN to send raiding parties of Fletchers deep into the Japanese lines to commerce raid. They think Japan could ever have mounted an air ASW campaign hundreds of miles out to sea, and damage scores of fleet submarines per year, sending them home. They don't know there were a total of 110 non-fatal attacks on subs in the entire war. They think subs were mainly useful for detecting passing carriers, off to win the war.
I know things won't change in the EXE. I'm just sayin'. I saw some of those WWII sub men when I was a boy. They'd come over to our navy housing apartment to see my dad when we lived at Pearl Harbor in 1960-61 and he was chief sonarman in USS Bluegill. (Which sank an IJN light cruiser from tubes I actually saw and touched.) This is a bit more real to me than to most players I guess. Anyway, Moose out.