Why didn't the Japanese army occupy Hawaii?

I am wondering why the Japanese didn't send ground troops accompanying the fleet to occupy Hawaii right after they launched the surprise air-naval attack on the Pearl Harbor? If they had taken over and controlled Hawaii, it would have been very difficult for the US navy to fight back on the Pacific Ocean because there is no other military base between Hawaii and the west coastal area of the US, and the distance is too far for the US to launch attacks on the well-prepared Japanese-controlled Hawaii from the west coast if it's not impossible. Had the idea (occupation of Hawaii) come across the Japanese decision makers' mind?

Quite simply, because they didn't have the capability to do so.

Mark Sieving

Hawaii was too far from Japan. They were worried about being overextended. They wanted to capture a larger area of the Pacific closer to Japan first. They captured Malaya, Singapore, Thailand, the Dutch East Indies, the Phillipines, the Bismarcks, the Gilberts, the Northern Solomons, Northern New Guinea and Attu and Kiska in the Aleutians. That's an awful lot of territory. After that their plan was to capture the Midway Islands and finish their conquest of New Guinea and the Solomons by capturing Port Moresby and Tulagi. These attempts were defeated at the Battle of Midway and the Battle of the Coral Sea. If these would have been successful, capturing New Caledonia and the Fiji and Samoa Islands would have been next. Then they would have completely cut Australia off from the rest of the Allies. They would then be in a good defensive postion that could be more easily defended by the amount of personnel available to them. Don't forget that they were also fighting in China, which was where the bulk of their army was, and where they also had to worry about being attacked by the Soviets.

At that time they were sldo occupying Southeast Asia and the NEI (where the oil and tin were). Without the soutern resource area there would not be enough raw materials to prosecute the war. zThere was no available shipping, either transport or war ship escourt, to transfer an occupation force. The logistics of keeping it supplied even if it were landed successfully were completely beyond the capabilities of the Japanese. Evening sending an occupation for to Midway in 1942 was wishful thinking, Logistically, they couldn't have kept it supplied even if they had taken it.

Think for a minute about what would be required. They would have to occupy at least three of the islands. To sustain such a force they would have had to have air and artillery as well. The carriers only had fuel to stay another day or two anyway. To maintain air cover over Hawaii they would have needed to capture runways intact, and then land the a/c, pilots, spares, fuel, etc., etc., etc. to make them operational. It was simply beyond their ability to sustain such a logistical effort.

On 11 Jun 2004 16:38:11 -0500, This e-mail address is being protected from spam bots, you need JavaScript enabled to view it (Lin Chi)

First thing comes to mind is that it would not have been able to keep open a supply line. While Japan could have landed in Hawaii, it would not have been able to keep it.

They didn't have the troops to spare. They were needed to attack the various other places the Japanese wanted to seize, such as the Dutch East Indies and their oil and other resources. Other logistics factors, such as the distance from Japan and Japanese bases, no doubt also played a role.

tim gueguen 101867

There are several reasons.

One is that the Japanese were short on shipping, and could only move a limited number of troops at a time. Since the idea was to move south and conquer the Dutch East Indies, and all territory on the way, far too little shipping would be left for Hawaii.

One is that the Japanese planned Pearl Harbor as a hit-and-run raid, and expected to take heavy casualties. The carriers were fast, and didn't have to get too close to Pearl Harbor to launch a strike. Troop transports would move much slower, and would have to reach the island itself to do any good. Until they reached it, they would be nothing more than targets with lots and lots of men aboard.

The Japanese would have to maintain sea superiority in order to launch an invasion, and the Striking Force was on a logistical shoestring. It took a lot of work to extend the range of destroyers and the smaller fleet carriers to launch the raid in the first place, and it would be essentially impossible to remain in place for a week.

This has been raised and demolished several times on this newsgroup in the past. For a full discussion, review any of the numerous prior threads on the subject.

In brief, however,

1) They didn't have the troops. Given the US forces on Hawaii on 12/7/41 (two division equivilents plus several thousand 'ashore' sailors [useful as static infantry if nothing else] plus units of the Hawaii NG), something on the order of four to six divisions were the minimum required for a successful invasion. Given the requirements for more pressing tasks - the invasion of Malaya, the Philipines, the NEI, and China, Japan didn't have the necessary troops available.

2) They didn't have the shipping. Japan was hard pressed to provide sufficient shipping for the invasions of the Philipines and Malaya - which were only several hundreds of miles from the nearest Japanese bases. Attempting to transport four (or more) divisions across several thousands of miles to Hawaii was beyond the capabilities of the Japanese merchant marine.

3) They didn't have the logistics. Even assuming they could have transported four (or more) divisions across several thousands of miles, they lacked the transport required to supply those troops. Putting troops ashore does little good unless you can keep them supplied with beans and bullets. Japan couldn't even do that at Guadacanal where the distance was shorter and the numbers of troops considerably fewer.

4) They couldn't maintain air superiority. The Japanese carriers carried only enough avgas and aerial munitions for about two days of operations and they had no capacity for underway replenishment. No later than 12/8/44, the carriers would have to withdraw back to the Marianas (at least) to replenish - leaving any Japanese troops 'on the beach' at the mercy of US aerial attack for a week or more.

Surviving US aircraft could be augmented by flights from California much quicker than that.

There were additional problems as well - for instance, Hawaii doesn't have any 'easy' beaches to land on and the Japanese had almost no suitable landing craft to make a beach assault. December is a particularly difficult time to be making an 'over the beach' assault - that's when the surfers flock to Hawaii to catch the really awesome waves.

In short, even a 'back of the envelope' calculation shows that a December, 1941 invasion of Hawaii is just not 'doable'. And the Japanese, wisely, never seriously considered such a thing.

Cheers and all,

The main US military presence was on the island of Oahu. The US had hundreds of aircraft there, the bulk of the Pacific fleet, and about 50,000 troops. Only a fraction of these were front-line combat troops, but even so, seizing Hawaii would require a substantial force - on the order of 25,000 men, or perhaps even 50,000. (As a general rule, an attacker needs three-to-one advantage at the point of contact. Attackers however have the advantage of deciding when and where the fighting will happen, and can concentrate forces against that point.)

The force which attacked Hawaii was 'Kido Butai', the Striking Force. It consisted of aircraft carriers, all fast vessels, escorted by two fast battleships, fast cruisers, and a dozen or so destroyers, also fast, a total of about 25 ships.

To carry out the attack, this force moved quickly across the vast expanse of the northern Pacific. The destroyers had to be refueled at sea in mid-voyage, as they could not carry enough fuel for the round trip. At-sea refueling was a new thing for the Japanese navy, and though they managed it, it was by improvised methods and with considerable difficulty.

Once the Striking Force had got near Hawaii, they ran in at top speed for a day to get in range for air strikes. The next day they sent in two waves of air strikes, then turned and got the heck out of the area, back toward their distant bases (and fuel supplies).

Now, had Japan wanted to _invade_ Hawaii, the fast vessels of the Striking Force would have been followed by a fleet of much slower troop transports and supply ships. At least 50 ships would have been required, and probably over 100. Not only would the Japanese need to bring 50,000 troops, they would have to bring every bit of ammo, food, and other supplies these troops would need for the entire battle. The nearest Japanese bases were thousands of miles away, and anything sent from these bases after the battle started would be too late to matter in the battle.

All these transport ships would require warships to escort them. (The Striking Force could not be assigned to this and still carry out its mission of air strikes on Oahu.) So 30-50 more warships would be needed. Thus the Japanese attack force would have expanded from 25 vessels moving quickly to 100-170 vessels moving slowly. The chance of this ponderous assembly escaping detection would be minimal, and the Japanese needed surprise.

The December 7 attack destroyed most of the UJS aircraft, and sank or disabled the battleship fleet, but there were still very substantial forces left - 20-30 destroyers, several cruisers, and two aircraft carriers.

The Japanese would have to carry out their landing operations while holding off these forces. The Japanese would be on the offensive strategically, but tactically on the defensive - their naval forces forming a cordon around the transports while the US forces could mass for a strike from any direction.

But even if the Japanese managed to get this 'armada' to Hawaii, _and_ get in a surprise attack on the fleet and the airfields, _and_ protect the landing force from the surviving American forces - how are they to get ashore? Japan had very primitive amphibious forces - none of special-purpose landing craft that the US developed and produced in huge numbers later on. All of the Japanese landings were against poorly defended or undefended coasts, using small boats to ferry men from ship to shore.

One partial exception was Wake Island - and the first Japanese attack there was driven off.

A final point. _Where_ would the Japanese invade Oahu? The south coast of Oahu, around Pearl Harbor, and east to Waikiki, was heavily fortified. In earlier pre-aviation years, US planners worried that enemy warships might steam up to near the shore, bombard the base areas and shell ships caught in the harbor. So they emplaced dozens of heavy guns along the coast there, including 14' and 16' guns. These guns were in rock-and-concrete bunkers that were all but indestructible.

The north coast of Oahu was not fortified, but it didn't need to be. That's where the world surfing championships are held. From Oahu the Pacific stretches thousand of miles north with nothing to break it up. The long waves that build up across this expanse pound north Oahu with 20 and 30 foot breakers. That's great for the surfers, but it would be certain death for soldiers trying to get ashore in small boats, loaded down with guns and ammunition.

Yes. In fact Japan drew up plans for the government of Hawaii under Japanese occupation. This was more of a self-indulgent fantasy than a real plan, though/

They lacked the naval strength. It is one thing to launch a surprise air raid, quite another to mount a full-scale ground invasion. Hawaii was heavily defended by the U.S. Army. Even if the Japanese could have successfully established a foot-hold, supplying the invasion forces that far from the nearest supply bases would have been extremely difficult. Troops in combat need a lot of supplies.

Look up the statistics on the vast logistical effort mounted by the U.S. later in the war to support their invasions of Japanese-held territory, and you can see the problem.