What Changes if the Japanese Didn't Attack Midway?

[FarAway Sooner]

With the benefit of hindsight, it's pretty obvious that the Japanese assault on Midway was a case of serious overreach.  Despite their long string of victories, the Japanese seriously diluted their most powerful offensive weapon in the whole Pacific Theater (their main carrier battle fleet) before sending it deep into hostile waters to conduct an undersized amphibious assault against a target of dubious strategic value. 

Even granting them the benefit of surprise, their navy enjoyed no real numerical advantages in planes or carrier striking power over the opposition that they were facing.  This was apparently driven by deeply disfunctional decision-making within the highest levels of their staff circles. 

The best source of documentation around the flaws in the decision making processes that led to the Japanese assault on Midway can be found in Parshall and Tully's Shattered Sword, but there's a growing body of evidence that suggests the Japanese misconduct of WW II was driven by a profound rift between the IJN and the Imperial Army, and a fundamentally flawed decision making process within the ranks of their high command that attached more importance to personal honor than to institutional effectiveness.

All of which is prelude to my main question:  What is the future of WW II in the Pacific if the Japanese hadn't chosen to attack Midway, and instead adopted a (at least slightly) more defensive force posture that retained their main carrier battle force?

[besilarius]

I think the situation comes down to what Yammamoto would choose.
He was, in effect, the chooser for naval strategy.  The Naval General Staff had bowed to his threat of resignation before Pearl Harbor was approved, and in reality never really opposed his plans for Midway, even though they recognized all the flaws that in hindsight make it such a reach.
If he did not hold out for Midway, the General Staff's preference was the South Seas aimed at the Guadalcanal -New Caledonia area.  This would threaten the lengthy supply chain to Australia, and likely force a confrontation that (at this point) the IJN believed they would win.
With six veteran carriers and aircrews, perhaps they would.  However, the IJN's penchant for dispersion of effort, led them to detach two carriers into the Coral Sea.  The net effect was that they accomplished very little except to keep Shokaku and Zuikaku out of the Midway operation.
If this prelimary show was ignored, and the whole of First Air Fleet moved to the Corfal Sea area, then the four american carriers with ground based air, would be a roughly even match.  (And if Wasp and Saratoga were not out from torpedoes, there might even have been parity in carrier decks.)
When you throw in codebreaking by Station Hypo in Hawaii, it seems that the odds would not favor this long maneuver.
The problem with any offensive by the IJN, was how fragile carriers can be and there were no replacements if any were damaged or sunk.  If they don't succeed quickly, and are forced to stand and take it, then carriers are very poor control mechanisms.  Eggshells with hammers.
Probably the best plan (but the one Yammamoto knew would ultimately fail) was to consolidate their island perimeter while conserving the First Air Fleet as a central reserve.
As Shattered Sword argues, the First Air Fleet had no real staying power.  It was a raiding force that could strike heavily, but had to depart quickly to avoid counterblows.

[LongBlade]

I think the situation comes down to what Yammamoto would choose.
He was, in effect, the chooser for naval strategy.  The Naval General Staff had bowed to his threat of resignation before Pearl Harbor was approved, and in reality never really opposed his plans for Midway, even though they recognized all the flaws that in hindsight make it such a reach.
If he did not hold out for Midway, the General Staff's preference was the South Seas aimed at the Guadalcanal -New Caledonia area.  This would threaten the lengthy supply chain to Australia, and likely force a confrontation that (at this point) the IJN believed they would win.
With six veteran carriers and aircrews, perhaps they would.  However, the IJN's penchant for dispersion of effort, led them to detach two carriers into the Coral Sea.  The net effect was that they accomplished very little except to keep Shokaku and Zuikaku out of the Midway operation.
If this prelimary show was ignored, and the whole of First Air Fleet moved to the Corfal Sea area, then the four american carriers with ground based air, would be a roughly even match.  (And if Wasp and Saratoga were not out from torpedoes, there might even have been parity in carrier decks.)
When you throw in codebreaking by Station Hypo in Hawaii, it seems that the odds would not favor this long maneuver.
The problem with any offensive by the IJN, was how fragile carriers can be and there were no replacements if any were damaged or sunk.  If they don't succeed quickly, and are forced to stand and take it, then carriers are very poor control mechanisms.  Eggshells with hammers.
Probably the best plan (but the one Yammamoto knew would ultimately fail) was to consolidate their island perimeter while conserving the First Air Fleet as a central reserve.
As Shattered Sword argues, the First Air Fleet had no real staying power.  It was a raiding force that could strike heavily, but had to depart quickly to avoid counterblows.

That is a far more informed view of what I would have shared, but I largely agree.

The Japanese naval code was confirmed broken by Midway, but it was broken regardless.

US industrial power would eventually eclipse anything Japan could put forward. Remember: we chose to fight Japan with one hand behind out back for most of the war - by prioritizing the ETO. I don't know how Japan could have won under any circumstance. Best thing they could have done is to never go to war with the US and hope we wouldn't eventually turn our attention to them when our inevitable war with Germany was ended.

[eyebiter]

Had Japan decided not to invade Midway or the Aleutian Islands in 1942, the Combined Fleet would have been in a better position to support combat operations around New Guinea and Rabaul.  Solomon Islands campaign in 1943 would have been more difficult for the American to supply.  Threat of Japanese carrier raids on Northern and Eastern Australian coast. 

However in the long run the extra carriers wouldn't make that much difference.

- Fuel shortages would limit how far KB could travel away from the Dutch East Indies. 
- Attrition among prewar carrier trained Japanese pilots would have eventually reduced the effectiveness of the KB.
- In 1944 Japan would still be using the A6M Zero, while the Americans deployed the F6F Hellcat in great numbers.

US industrial power would eventually eclipse anything Japan could put forward.

Good article on the Combined Fleet website (authors of Shattered Sword)

Why Japan Really Lost The War
http://www.combinedfleet.com/economic.htm

[besilarius]

Thanks Biter, that's a great article.

[bob48]

Very interesting, and some staggering facts there.

[GDS_Starfury]

all things being what they were I dont think Midway was overreach.  there was a TON of luck that let us win that.
overall though I dont think the outcome overall would have changed much.

[LongBlade]

all things being what they were I dont think Midway was overreach.  there was a TON of luck that let us win that.
overall though I dont think the outcome overall would have changed much.

I agree we had luck on our side there. Perhaps a case of fortune favoring the bold?

[FarAway Sooner]

There was certainly some luck involved.  That said, I think it's exaggerated.  Or, as others have said, luck is where preparation meets opportunity.

Once you acknowledge that the Americans had broken the Japanese codes and would have a carrier group near Midway to greet the Japanese fleet, most of the "luck" goes out of the equation.  Elements of "luck" that have been attributed to the US in the Midway Battle that Parshall and Tully pretty methodically debunk in Shattered Sword, largely by drawing on Japanese sources:

• The Japanese enjoyed a numerical and qualitative edge in terms of the planes and personnel committed to the battle.
• Americans caught the Japanese carriers rearming their planes for a second strike, with catastrophic results.
• The delayed search launch of the Japanese search plane Tone 8 delayed finding the American fleet, but did little to change the flight operations of the Japanese carriers.  Once the first attack wave took off for Midway, the Japanese die was largely cast.
• The American torpedo bombers drew the Japanese CAP down to sea level, so they couldn't then rise to meet the American dive-bomber squadrons coming in at higher altitudes.

Are there other instances of luck that you're referring to, or do you take issue with any of those assertions from above?

[GDS_Starfury]

the US Navy finding the Japanese first is borderline luck.

[besilarius]

Even Nimitz recognized that luck was an essential element.
The rendezvous point for Task Forces 16 and 17, north of Midway, was designated by him as Point Luck.
The pilot who first spotted the Japanese was Howard P. Ady.  This was irony on a truly cosmic scale.
His wife was in their home outside of the base on 7 December, 1941.  The planes flew over her all through the attacks, and the house was seriously damaged by anti-aircraft rounds that came down.  She was seriously traumatised, and really never recovered.
Ady, called Junie by his family, always regretted that he was a PBY pilot and not in an attack squadron.

[Staggerwing]

Well, it's probably safe to say his personal contribution had as much impact on the outcome as any other single USN pilot did.

[GDS_Starfury]

and those little twists are why I love history.

[FarAway Sooner]

The U.S. finding the Japanese was certainly fortunate.  BUT, the presence of long-range PBY Catalinas anchored in an indestructible runway at Midway certainly gave the Americans vastly superior reconnaisance capabilities to the Japanese.  If the Japanese wanted to attack Midway, they had to be well within the US search radius, and (due to longer time aflight) those planes could cover much more ground within a given time frame than the Japanese planes could. 

And the US had significant submarine elements in the area, which enhanced the likelihood of detecting the Japanese at any given point in time.  So, while finding the Japanese did involve an element of luck, it was luck enhanced by superior resources and tactical advantage.

Midway itself was easily found, but also much harder to knock out of commission (and obviously impossible to sink) and packed formidable AA.  The Japanese certainly could have pounded Midway into rubble had it not been for the arrival of US carriers.  But, if you look at the damage reports on the Japanese planes from the first strike, it's obvious that the Midway defenses took a definite toll on the Japanese air arm.

Again, knowing where and when the Japanese were coming was a huge advantage.  But even that wasn't just pure luck.  Significant American efforts (in terms of technology and manpower) had gone into code breaking.  There was some luck there, but again, it was where preparation met opportunity.

I agree with the overall assessment.  Guadalcanal never happens if the Japanese don't attack Midway, which probably means that Allied progress in the South Pacific is probably delayed 9 months or more.  At the time, Guadalcanal seemed like a dead-even slugging match, and it was very real to the numerous soldiers who fought there. 

But it was really just a grinding war of attrition which decimated the Japanese air force while the Americans mustered their forces for a knock-out blow in late 1943 and 1944.  The production figures that Parshall provides on the link mentioned above really illustrates this. 

Once the Americans got rolling, the Japanese were never going to have the forces to stop them.  The Japanese simply obliged the Allies by sending their main strike force within range of unopposed land-based air forces for the first time, which freed up the Americans for a war of much more maneuver in the South Pacific.

In the end, the Japanese were doomed by American industrial might and their own refusal to build enough escort ships.  That, combined with a limited merchant marine and extended supply lines (i.e., relying on petroleum from the Indies), had Japan doomed to failure before they really got started.

[Windigo]

Japan's real mistake was not declaring war on the Soviet Union and keeping those Siberian troops in place