New Movie Alert! "Midway", coming November 2019!

I had forgotten about this article:
The Hawaiian Invasion, and other Nonsense
It does assume a 12 Aug 42 invasion initially but has some interesting data points:

That's approximately enough for a 1:1 confrontation if my memory serves.

[qutoe]... Big Reason #2 is that the Japanese, even at the zenith of their military power, never had anywhere near the logistical capability or the amphibious expertise to transport 60,000 troops to a remote landing site, land them under enemy fire, provide them with sustained gunfire and air support, and keep them supported throughout what could easily be a month-long campaign. The invasion of Malaya, which was the single largest Japanese amphibious operation of the war, had involved a scant three divisions, and they hadn't been landed all at once, nor had they been landed into the teeth of concerted enemy fire. Furthermore, the Japanese invasion convoys in that campaign had been operating from bases in French Indochina (Vietnam), which were a few hundred miles from the Malayan beaches. British airpower was dispersed, and unable to concentrate against the Japanese landings. By contrast, Hawaii is some 3,900 miles from Japan, and almost 2,300 miles from Truk, which were the only staging areas developed enough for such an undertaking ...[/quote]

Then it goes on to look at a 7 Dec 41 invasion:

It goes on covering some points we have and some others but I think I've quoted enough for now and it's a short easy read.

 

The question is how many did they have in November of 41? I have found that the IJA ordered over 3,000 of them but only 40 were known to have been built in 42 (greater production is assumed). See for instance:
The Pacific War Online Encyclopedia: Daihatsu Class, Japanese Landing Craft
Then there were some larger ones of which the navy ordered 163 with production starting in 1940 but running through 44.
The Pacific War Online Encyclopedia: Toku Daihatsu Class, Japanese Landing Craft
Pacific Wrecks
does say that around 6,000 were built but no clue as to when.

 

They had ramped landing craft as early as 1937, when they were photographed by then Lieutenant Victor Krulak USMC in Shanghai (Krulak later advised Andrew Higgins on incorporating a ramp into his landing craft). And of course the Japanese conducted beach landings at Kota Bharu, Lingayen Gulf, and other points in 1941.

 

But did they have enough for 2 or more divisions to be landed at one time?

 

Like everything Japanese, the issue is complicated by the intense rivalry between the IJA and IJN. The landing craft and ships were all IJA developed and funded until 1942 when the IJN finally got interested and started purchasing craft to the army designs and took over some of the army-designed ships being built, then designed and built their own LST-type ships. AFAIK, up to December 1941, there was exactly one (1) Japanese Army amphibious landing ship, the Shinshu Maru.

The Army first designed the Shohatsu, a 10-meter landing craft without a ramp in 1927 and built about 1,000 by 1943, the Navy bought 20 starting in 1944. The larger ramped Daihatsu was designed in 1930 and the Army built some 2,700-2,800 of them by 1945, while the Navy began purchasing them in 1935 and eventually bought 3,229. The first tank-capable Toku Daihatsu was designed by the Army in 1940 and production began in 1941 with a total of about 200 built for the Army by the end of the war, while the Navy bought 163, starting in 1943. The larger Moku Daihatsu was designed in 1942 and several thousand were built for the Army and 1,140 for the Navy.

All of the Army ships and craft were slated for operations in China and Indochina prior to 7 December 1941 and then for the Southern Operation beginning 7 December. It is unlikely they would allow the Navy use of any of them. That leaves the Navy with however many of the 3,229 Daihatsu built for them 1935-1945...I would estimate numbers in the hundreds might be available. However, the Japanese calculated it took at least 40 minutes to load troops and equipment in the 29 Daihatsu carried on the purpose-built Shinshu Maru...and 17 hours to unload 4,000 MT of cargo from a single transport ship using two Daihatsu. And that was under good conditions on a calm sea. So call it a couple of hours standing offshore loading under the guns of the Coast Artillery. Going by the Marus that were eventually converted, perhaps 20 Daihatsu could be carried assuming the Navy did the conversions early enough, but in the real world that took between 6 and 22 months from initiation of the conversion to completion.

 

The big IF remains whether or not the Army would agree to such a hare-brained Navy operation. If so, they have one purpose-built transport capable of carrying 2,200 troops and 29 Daihatsu...all the rest would be improvised. Assuming triangular divisions that would be six assault regiments...and at roughly 1,200 per battalion that means 21,600 men, so roughly 310 Daihatsu...which means at least 14 transports in addition to Shinshu Maru. Just to get the assault elements of the infantry ashore.

 

The landing force for Kota Bharu on Dec 8 comprised one infantry division, an additional regiment, tank, engineer, and other supporting units. Various minor landings in places like the Philippines were also executed. They had to make a second trip to bring in the remainder of 25th Army, making a total of three divisions and attachments. Then on Dec 22-23 they landed two divisions and supporting units at Lingayen and Lamon Bays on Luzon. I don't know if the same transports were used, but the timing makes it seem likely. So, two divisions with attachments seems to be about their capacity.

Again, we don't know how many of ships involved had the range to make it to Hawaii. Staging somewhere like the Marshalls would increase the chance of detection and putting the Americans on alert.

And of course they would be postponing the assault on their main objectives in the Far East for as long as it took to complete the Hawaiian operation, sacrificing the advantage of surprise, and giving the British and allies additional time to prepare, reinforce, and strategize.

 

Under the defense scheme that Alert 1 was a part of, the 25th Division's 35th Infantry basically was responsible for the area of the western beaches, from Wainae to Ewa, with one battalion fully motorized as a reserve. The 27th Infantry was responsible for central Oahu from Schofield down to Pearl, Honolulu, and Waialae. The smaller two-battalion 298th Infantry was responsible for the Kaneohe area and eastern beaches. I believe the 24th Division deployment was basically a mirror image for the northern part of the island, the 19th Infantry defended the north shore beaches, the 24th Infantry was deployed from Schofield north to Waialua and Haleiwa, with one battalion in motorized reserve, and the 299th Infantry along the eastern beaches from Kaawa north (I don't have as much clarity on them.

The difference between Alert 1, 2 and 3 was the mission emphasis, rather than deployment area. Alert 1 was focused on internal security protecting installations and vital points within the area of responsibility, 2 and 3 were more directed at an outward threat to the area of responsibility.

But then, I'm preaching to the choir.

 

Yep, and she was fast, but as a troopship she only carried 1,200-1,400 passengers and had no means of stowing Daihatsu without extensive conversion work, which might have been noticed, given she arrived in San Francisco on 30 October 1941.

 

Not sure that exists, at least insofar as I have found. The AA locations were pretty much the harbor, Wheeler, and Hickham, with secondary allocations to Schofield. Ewa and Kaneohe were Navy/USMC responsibilities.

 

The problem is a lot of it focuses on what they did - Alert 1 - rather than what they did not do.

I feel your pain...I spent an hour or so the other day looking for some documents for Anzio, before I suddenly realized I didn't have copies and the originals were in Northern Virginia, about 2,400 miles east of me...

 

Regiment Battery In position and ready to fire
64th (Alerted at 8:15 a.m.)
A (searchlight) at Honolulu 10:00 a.m.
B (3-inch) at Aiea 10:00 a.m.
C (3-inch) at Aliamanu 10:30 a.m.
D (3-inch) south of Aliamanu 11:00 a.m.
E (searchlight) at Ewa-Pearl Harbor (Time not known)
F (3-inch) at Pearl City 11:05 a.m.
G (3-inch) at Ahua Point 10:30 a.m.
H (3-inch) at Fort Weaver 10:00 a.m.
I (37-mm) at Aliamanu (Known only that
K (37-mm) at Hickam Field batteries in position
L (37-mm) at Hickam Field before 11:45 a.m.)
M (37-mm) at Wheeler Field 11:55 a.m.
97th (Alerted between 7:55 and 8:10 a.m.).
A (searchlight) at Fort Kamehameha 8:34 a.m.
F (3-inch) at Fort Kamehameha 8:55 a.m.
G (3-inch) at Fort Weaver 8:30 a.m.
H (3-inch) at Fort Barrett 10:20 a.m.
98th (Time alerted not known.)
A (searchlight) at Schofield Barracks
B (3-inch) at Schofield Barracks 9:55 a.m.
C (3-inch) at Schofield Barracks 10:30 a.m.
D (3-inch) at Puuloa Dump, south of Ewa 11:45 a.m.
F (3-inch) at Kaneohe Naval Air Station 1:15 p.m.
G (3-inch) at Kaneohe Naval Air Station 1:15 p.m.
H (3-inch) at Waipahu High School 1:30 p.m.
251st (Time alerted not known)
A (searchlight) at Ewa
B (3-inch) at West Loch 11:45 a.m.
C (3-inch) at Ewa Beach 11:45 a.m.
D (3-inch) at South of Ewa 11:45 a.m.
E (50-caliber) at Navy Yard Pearl Harbor 12:41 p.m.
F (37-mm) at Navy Recreation area 12:30 p.m.
G (37-mm) at tank farm, Schofield Barracks 11:00 a.m.
H (37-mm) at Navy Yard 12:05 p.m.

One antiaircraft detachment was located at Sand Island when the attack started and engaged the enemy with 3-inch guns at 8:15 a. m., shooting down two enemy planes at that time.

Note that most of the 37mm batteries were actually equipped with .50 caliber MG.

 

Seriously, the only viable beaches the Japanese might consider are the west side from Kaena Point SE down to Barbers Point or the eastern side from Kaneohe Bay NE to Kaaawa...which of course had also become bleedingly obvious to the Hawaiian Division in the previous twenty years. Then, of course, there is the not so minor problem that the 24th and 25th ID had just returned from the field on Saturday, following the nine days on alert after the war warning. AFAIK, the only thing they did different when they went out on Sunday was the laying down of the concertina, pickets, and trip wire obstacles. All the best positions and fields of fire for the machine guns and beach guns had been calculated and laid out over years of doing the same exercises over and over.

Granted, the choice of beaches sounds poor. (Perhaps the element of surprise would make some difference?) This scenario was just me flying a kite... by all means point out the difficulties or impossibilities, but please don't presume that I do not know quite a bit - some posts sound like a lecture, especially when it is NOT new info (to me) that you are relaying. Since I am not impressed with the Japanese strategic planning, that is why I was thinking out loud about how it might have been improved. If there were a way to improve it (granted, potentially a perfect plan with hindsight), it would still be of some historical interest to know that the Japanese failed to maximize the possibilities of the situation; that they missed something that may have worked better. Could they have taken Hawaii, still focusing on the Dutch oil, but by delaying Philippines and using those forces? Sounds highly unlikely, but it was interesting to explore this. The key issue, beyond shipping & supply (problematical), scarcity of troops (but fanatical), is the problem of the fuel oil. Capture of the Tank Farms would have hurt the U.S. Navy, but NOT crippled it. To me that was the key factor. That made the plan not even worth considering, because taking the region (even in unlikely event it could happen) would ONLY have been worthwhile if the Japanese could HOLD it for awhile. (With the U.S. Navy still having fuel oil and being mobile, counterattack & recapture would be almost immediate.) Thank-you Richard for filling in info I did not have. Had this Hawaii option been viable, would the Japanese win the war? - of course not! The economics would still be clearly against them. Holding Hawaii would have bought time. However, if the Germans actually did better (than historically) in their half of the war, necessitating the U.S. to go with a "Europe Only" strategy (over "Europe First"), then in this case maybe an armistice could have been signed between the U.S. & Japanese. (This is the only imaginable way that the Japanese come out okay in WWII.) The Hawaii Option - not working. I will put this "what if" to bed, now. (Perhaps you did not enjoy this "what if" - but the information that was forthcoming, was valuable.)

But while I'm at it, I wanted to point out other Axis strategic problems. They insisted on having their "parallel wars" rather that actually cooperating. This was in their nature, (I am well aware of this, so no need to lecture me on it) so any talk of them cooperating better, is also "what if". Nazi Germany, fascist Italy, and militaristic Japan did not trust each other enough to share plans. They even worked at cross-purposes at times. Italy failed to inform the Germans of the Greek fiasco, until it was underway. The Germans failed to inform the Japanese of Barbarossa. The Japanese failed to inform the others of Pearl Harbor. (I am reminded, when I think of the Axis, of three bank robbers that fight each other over their share, after the bank job. Greedy, and just not too bright.) For all the OPERATIONAL expertise of the Germans, they performed very badly, in STRATEGIC terms. When staff officers did point out logistical problems, they were usually overridden. At some point, every member of the Axis swallowed hard, and tried to convince themselves that they could beat the combined economic factors of Britain-Soviets-USA.

I think there is no doubt, looking back, that many possibilities were missed, due to the lack of cooperation. Khalkin-Gol had convinced the Japanese to leave the Russians alone. But if Hitler had informed the Japanese of his Barbarossa plans some months in advance, they might have considered the advantages of an advance on the Soviets simultaneously from east and west. (This would have been BEFORE the Southern Option was fully put in place. The oil of the Dutch East Indies would still have to be taken, but maybe some other Southern moves could be scaled back.) Capture of other oil (Baku, mid-east) might also become possible. Had the Germans considered Italian interests, they may have done better in the Mediterranean. (Any of Suez, Malta, Spain/Gibralter & British mid-east Oil, as potential gains) A Mediterranean option could lead to Axis presence in the middle east. German advances in the Caucasus and any Axis presence in the middle east, would compliment each other, making each of these advances more potent. Step one to any Med. Option, would have been providing a reasonable amount of fuel oil to the Italians, so their fleet could actually leave port more often. It would also have required more German ground forces in the Med, at the expense of slightly less for Barbarossa, or some delay in the start time of Barbarossa. Japanese amphibious moves from the Indian Ocean, may have coordinated nicely with the other Axis forces in Africa. To do this, some Japanese transports, troops, and CV's would have had to skip another of the historical operations (perhaps New Guinea & the Coral Sea?). The pay-off would be a linking of the Axis through the middle east, and capture of Oil. This Oil would have given the Axis more ability to compete in terms of the economics, and such a link-up would have spelled trouble for the Allies - both in strategic (India endangered) and logistical terms. Not all of these gambits could be done, but I am just thinking out loud again, pondering the possibilities. (I am merely painting in broad strokes here...try to resist the urge to jump all over this.)

 

Regiment Battery In position and ready to fire
64th (Alerted at 8:15 a.m.)
A (searchlight) at Honolulu 10:00 a.m.
B (3-inch) at Aiea 10:00 a.m.
C (3-inch) at Aliamanu 10:30 a.m. (ETC, ETC...)

This is some great info, that I would love to plot on a map...but this is a problem I run into often - a lack of decent WWII-era maps. Does anyone know of WWII-era maps of Oahu, showing reasonable detail ?