I've been gathering up a lot of information about the Pacific War and most of the threads I've seen at some point mention how the Japanese were on a tight schedule and how Japanese needed everything to go just right. I'm wondering what was the Japanese contingency if their coup d'main turned sluggish. Like had the invasions of Malaya and Philippines bogged down quickly and the Japanese suffered high casualties, what was Japan's plan? Just send in more troops and if so where would these troops come from? Also how would the bogged down campaigns affect the other campaigns the Japanese were launching in early 1942, or this the "tight schedule" over exaggerated?
Question on the Pacific War
- Thread starter Gurroruo
- Start date
Admiral Halsey
Banned
IIRC they had no plan B. It was an all or nothing gamble really and to the detriment of the allies it worked.
If the first attacks had failed they'd have doubled down with more invasions. The additional troops would have to come from Korea and China, with a couple more divisions in Japan proper. The oil reserves were adequate for a year or more of fighting.
The Japanese had limited lift, the IJA was also less than entirely enamored with the diversion of resources from the main battle, which was the conquest of China.
The South Seas Detachment was used to take both Guam and shortly thereafter Rabaul. The 48th Division, used as the main assault force on Luzon was also the main force for the DEI, and so on. The same was true for SNLF units, all of which were multi-tasked, sometimes without even being given time to refit after action.
The time it would take to reinforce is dependent on where the forces came from and if they had the proper equipment ready to load. You can load troops who happen to be in a port in fairly short order (if the transports are in the harbor figure four days, just to get the troops and their personal equipment loaded, longer for any heavy equipment), if the same division has to move from Manchuria with all its equipment it is a different matter.
Minimum one-way transit time to Borneo would be a week to ten days if the unit was in Japan, similar for Korea, two-three day longer for the rest of the DEI.
Assuming a month overall, from decision that the unit is needed until it arrives would be in the ballpark for a coastal unit, six weeks or more for units that had to make movement to reach embarkation. If the unit was engaged, opposed to garrisoning, added time to refit is likely to be needed.
The Japanese had, at the max, six months, by their own estimates, to achieve their goals, which were to secure the resources needed and set up a defensive perimeter. Clearly, a six week delay in their initial goals was a huge deal. They would, however, have found the force to make the attempt (the best example being the meatgrinder of the Solomons, where the IJA was always finding units to feed into the action from somewhere).
The South Seas Detachment was used to take both Guam and shortly thereafter Rabaul. The 48th Division, used as the main assault force on Luzon was also the main force for the DEI, and so on. The same was true for SNLF units, all of which were multi-tasked, sometimes without even being given time to refit after action.
The time it would take to reinforce is dependent on where the forces came from and if they had the proper equipment ready to load. You can load troops who happen to be in a port in fairly short order (if the transports are in the harbor figure four days, just to get the troops and their personal equipment loaded, longer for any heavy equipment), if the same division has to move from Manchuria with all its equipment it is a different matter.
Minimum one-way transit time to Borneo would be a week to ten days if the unit was in Japan, similar for Korea, two-three day longer for the rest of the DEI.
Assuming a month overall, from decision that the unit is needed until it arrives would be in the ballpark for a coastal unit, six weeks or more for units that had to make movement to reach embarkation. If the unit was engaged, opposed to garrisoning, added time to refit is likely to be needed.
The Japanese had, at the max, six months, by their own estimates, to achieve their goals, which were to secure the resources needed and set up a defensive perimeter. Clearly, a six week delay in their initial goals was a huge deal. They would, however, have found the force to make the attempt (the best example being the meatgrinder of the Solomons, where the IJA was always finding units to feed into the action from somewhere).
Plus the British and Dutch get 6 weeks extra time to build up their defenses and prepare to destroy the oil wells if it looks like the Japanese are going to take them. That means that Japan will have to take far more casualties and it could all be for naught.
Guesswork? Maybe 3 weeks to march back from the front to port and say 1 week to embark, 1 week in transit, 1 week to debark, 1 week to the front so maybe 7 weeks?
This option might have been a pure theoretical assumption, but it was completely unrealistic, as the war in China alone consumed already some 90% of the IJA wareffort and the rest already was deployed in the Pacific, with no spare. So no troops would be diverted from the primary front (China) to the secondary front in the Pacific. China was Japans main goal, at least to the Army, who also commanded politics at the time. The Pacific was a sideshow in their oppinion, primarily a Navy playground, not the Army's.
On the question of the butterfly effects, a slower conquest of Malaya (say by a fluke the Japanese bombers don't find Force Z and it manages to disrupt the landings significantly) might mean no invasion of Burma (or a later invasion, giving the British time to prepare), e.g. if the forces used for Burma had to be diverted to Malaya. This has a major butterfly if the Burma Road stays open, greatly easing China's situation relative to OTL.
A delay in the Philippines might mean the Japanese can't or at any rate don't follow up their success at Rabaul with an invasion of New Guinea (which in turn perhaps butterflies the Solomons Campaign). An unsubdued Singapore might delay or prevent the Indian Ocean Raid by the IJN. This in turn might butterfly away the British invasion of Madagascar. And so on.
A delay in the Philippines might mean the Japanese can't or at any rate don't follow up their success at Rabaul with an invasion of New Guinea (which in turn perhaps butterflies the Solomons Campaign). An unsubdued Singapore might delay or prevent the Indian Ocean Raid by the IJN. This in turn might butterfly away the British invasion of Madagascar. And so on.
This seems like an appropriate thread to ask a question I've been wondering about for a little while but how much trouble could Sharp and Chynoweth have caused with their Visayan-Mindanao Force if it was an independent command rather than put under Wainwright? That way when Wainwright retreats to Bataan and later becomes trapped on Corregidor he can honestly reply to the Homma that he doesn't have the authority to surrender those forces.
I'd guess any redeployed troops would come from the Kwantung Army or Home Islands.
Consider something else, tho: if Japan does even slightly less well, & (frex) Guadalcanal gets butterflied somehow, it could make things better for Japan in the medium term.
The fewer islands she takes, the easier it is to avoid losses in shipping supplying them, & (especially for Guadalcanal) burning fuel doing it.
Diversion of troops, OTOH, offers opportunities to interdict them, both for USN subs & Allied aircraft. (Battle of the Bismarck Sea, anyone?) This could have very unpleasant consequences. OTL, reinforcements bound for the P.I. were intercepted by submarines & ended up on Okinawa & Iwo Jima...
It's never simple, is it?
Consider something else, tho: if Japan does even slightly less well, & (frex) Guadalcanal gets butterflied somehow, it could make things better for Japan in the medium term.
The fewer islands she takes, the easier it is to avoid losses in shipping supplying them, & (especially for Guadalcanal) burning fuel doing it.Diversion of troops, OTOH, offers opportunities to interdict them, both for USN subs & Allied aircraft. (Battle of the Bismarck Sea, anyone?
) This could have very unpleasant consequences. OTL, reinforcements bound for the P.I. were intercepted by submarines & ended up on Okinawa & Iwo Jima...It's never simple, is it?
They can be a problem, but more of the irritant variety. The only "professional" forces under their command was one battalion of Philippine Scouts. The rest of the forces included one "regular" Philippine Army division (completed training, full TOE for the Philippine Army, which was far less robust than a comparable U.S. Army formation), and a number of freshly "stood up" divisions that were actually mainly untrained, or barely trained, militia, many without either weapons, or, if they had weapons, limited or no ammunition.
Hunting them down would have taken some time and effort, especially if the U.S. commanders used the Scouts as cadre and set up small local commands with responsibility to resist, but to avoid, to the extent possible, set-piece actions. They lacked artillery, automatic weapons and even grenades, in a main force they had no chance, as small units, they could have been a pain in the ass to the IJA for years. Still, pain in the ass =/= victory, or the ability to tie down multiple additional top line divisions.
Basically yes, a all or nothing gamble. Any of the leaders who gave any thought to it (& not all did) knew they could not win if the enemy carried the fight into a year or more. The only winning plan anyone could come up with was 'They will wimp out in a few months, & ask for a armisitce in six or less.' So a maximum effort was made to shock the Allies into submission.
John Costellos 'The Pacific War' has a readable set of chapters on this & the context of Japan larger situation. 'Japans Decision for War' is a more detailed study of the specifics of the decision for war & strategy.
Quite. The very few, like Yamamoto, who gave any thought to it could only come up with another round of the same. Which was problematic since their navy was not able to sustain expected losses and remain effective, their cargo shipping was wholly inadaquate, and of course fuel reserves not adaquate.
In the case of cargo ships & petroleum fuel there was on paper a years worth of combat reserves. The trick is the industrial managers told the navy they would be badly damaged by the first six months of use of those cargo ships and fuel reserves for Pacific military operations. The Navy told them to plan on having late 1941 levels of acess to cargo ships and fuel reserves for industrial use by June/July 1942. When the US failed to beg for a cease fire in four months the Navy had to tell the industry managers they would continue to to lack cargo shipping and restoration of the previous fuel allotments. Thus while additional Pacific operations could be attempted in the second half of 1942 it was at the expense of further severe degradation of industrial output.
That was fairly nonsensical in itself, since IJA & IJN would be using most of Japan's existing capacity, leaving about a third (IIRC) for civilians, when Japan's merchant fleet prewar was already below what she needed to sustain her industry...
Yes it was nonsensical from a well informed analysis. In the case of Japans industy they were told their X(.6) of pre embargo cargo fleet would be reduce to X(.2) or whatever for six months & then restored to X(.6) after that with the hope of seeing it restored to 100% of the pre embargo cargo fleet as peace negotiations bore fruit. Instead they were faced with crippling along on X(.2) or .3 & a hope that a crash construction program would bring that back up to .7 or .8, maybe.
Note: numbers above are for general illustrative purposes. John Ellis 'Brute Force' gave Japans 1939 or 1940 cargo shipping service volume at between 10 - 11 million tons. The removal of foreign flagged ships by the trade embargos in mid 1941 reduced this to approx six million tons of the Japanese flagged fleet. Their emergency construction program started in later 1942 launched between 3 & 4 millions tons in 1943-44. Over 8 million tons were sunk, mostly in 1943-44.
Approx 800,000 tons of cargo shipping were captured in early 1942 & about 400,000 tons of existing construction launched in 1942. In 1943 the USSR resumed cargo shipping to Japan, but I have no idea what that might have been in volume.
We aren't discussing GDP we're discussing imports and merchant fleet. They are different things.
I suspect a lot of that GDP represented effort going into sinking assets, like the cargo fleet. That peaked in 1943 & started shrinking the same year tho a increasing portion of the nations GDP went into it. Infrastructure was another factor. Japanese industry started retroconversion from petroleum to coal, the chemical industry entered a major construction program (that failed to pay off due to a catastophic fire ). The GDP in part represents a intense but failed effort to compete in a long term war.
There were three full-strength IJA divisions available in Japan in December, 1941, that could have been used elsewhere if need be: the 7th, which stayed in Japan throughout the war, other than the 28th Infantry Regiment (the Ichiki Detachment) which was destroyed on Guadalcanal; the 52nd, which didn't deploy until Nov '43 to the Carolines (and was bypassed at Truk, Yap, and other locales), and the 53rd, which didn't deploy until early '44 (to Burma). One other division in Japan (the 54th) was earmarked for Java, and deployed in Feb '42.
FYI the division that reinforced the 14th Army for the Bataan finale was the 4th, which had been in Shanghai prewar.
FYI the division that reinforced the 14th Army for the Bataan finale was the 4th, which had been in Shanghai prewar.