Savo Island

[T. A. Gardner]

Not only were enemy forces completely mis-estimated, but the casualties suffered were grossly out of proportion to actual results. If Mikawa thought just nine transports were present, and two damaged, he might well have thought the US landing force was just 1000 to 2000 men at most and already all but defeated. No need to engage the transports...

THAT might be the best point of all, and it is born out by the fact that the first group landed by the Japanese to wipe the Marines out was only a Battalion in size.
.... a Battalion by Japanese reckoning, anyway!

The battalion that was sent was what could be moved immediately. The rest of the Regiment was to be transported later. Ichiki was to wait for the rest of the Regiment, however, his unopposed landing & finding little in the way of US defenses, led him to grossly underestimate the US opposition. This, led to his decision to attack without waiting, and his unit got slaughtered.

Actually, the Ichiki detachment was one of the units originally intended for landing on and taking Midway. Colonel Ichiki was so determined to get into combat with the US at Guadalcanal--where the IJA believed the landing forces of the US numbered about 2000 men, or what the Japanese Army would have landed with--that he split his detachment into two units. The lead one had about 900 infantry and went to Guadalcanal on destroyers to get there quickly. The other about 600 troops with heavy weapons, light artillery, etc., followed in transports.

Yes, the Ichiki detachment was about the only immediately available force, but the IJA didn't order Ichiki to wait until he was reinforced before engaging the US in combat. They let him land and launch a hasty assault on the US positions getting his forces wiped out. It was really just arrogance and over confidence on the IJA's part.

[Carl Schwamberger]

Looks like three things influence Mikawas decision.

1. Doctrine of priority to engaging warships.

2. Poor intelligence on enemy. That is the underestimate of the amphib force. That reinforces #1 Why diverge from the strategy if the enemy support fleet is not large enough to be important?

3. Assumption that the US action was a raid that would be withdrawn very soon. The Japanese leaned towards the USN action being a raid as that had been the principle US action the preceding seven months. Destroyers raiding the amphib force at Balikapan, Carriers thrice raiding near Rabual/Solomons/New Guinea. Carriers raiding the Marshals & the Home Islands, landing parties on Main. Multiple air raids on Rabual. This assumption reinforces #2 & circles back to #1. Defeating the warships is the focus since the amphib force is only a 3000 to 5000 man raiding group.

Altering Japanese doctrine is the most difficult, so the faulty intelligence and faulty analysis behind #2 & #3 need to be changed enough to discard doctrine. I'm guessing the Japanese deciding the US action was a strategic move & not a simple raid would have been the simplest PoD. In that context they would have a larger incentive to continue attacking that night, and they might have interpreted their intelligence better.

[Takao]

5. Unknown location of US Carriers that are known to be operating in the area. If Mikawa dawdle too long, he exposes his cruisers to US carrier retaliatory strikes.

6. Overclaiming of land-based IJNAF on damage inflicted to US ships. Further, if IJNAF was so effective, they could mop up whatever was left behind.

7. Preservation of Japanese heavy cruisers, as no more will be forthcoming for the foreseeable future. This dovetails with 5.

[Huszar666]

Actually...

According to his best estimate the Allied force then numbered but one battleship, three cruisers (one of which was badly damaged) seventeen destroyers, and nine transports (two of which were burning).

Mikawa faced 5 heavy cruisers and a few destroyers, out of his best estimate of 3 heavy ships. Since he faced two more ships than the planes reported as battle ready, I'm quite sure he discarded the recon figures and did the sensible thing: retired.
If he was promised only 3 heavy ships while engaging 5, and 17 destroyers, while engaging only a few, he could have faced anything between 17 and 28 destroyers. At night, in crowded waters. And himself having only one destroyer.
With the destroyer- and torpedo-heavy Japanese doctrine, I doubt there were any thought given to sail into torpedo water and hope for the best.

[Carl Schwamberger]

True. They did assume the US torpedos were at least half as good as theirs, & likely nearly as good. Did the Japanese have evidence otherwise then?

[T. A. Gardner]

Actually...

According to his best estimate the Allied force then numbered but one battleship, three cruisers (one of which was badly damaged) seventeen destroyers, and nine transports (two of which were burning).

Mikawa faced 5 heavy cruisers and a few destroyers, out of his best estimate of 3 heavy ships. Since he faced two more ships than the planes reported as battle ready, I'm quite sure he discarded the recon figures and did the sensible thing: retired.
If he was promised only 3 heavy ships while engaging 5, and 17 destroyers, while engaging only a few, he could have faced anything between 17 and 28 destroyers. At night, in crowded waters. And himself having only one destroyer.
With the destroyer- and torpedo-heavy Japanese doctrine, I doubt there were any thought given to sail into torpedo water and hope for the best.

This is one version of Mikawa having such poor and conflicting intelligence that withdrawal in the face of having won a naval victory makes sense. This is reinforced by the IJN - IJA rivalry where the IJN in all likelihood doesn't give a s**** what the IJA's problems at Guadalcanal are.

[Carl Schwamberger]

Im contemplating what my next naval miniatures game might be...

[paulrward]

Hello All :

#21 by T. A. Gardner » 04 Jun 2022 17:37
This is one version of Mikawa having such poor and conflicting intelligence that withdrawal
in the face of having won a naval victory makes sense. This is reinforced by the IJN - IJA rivalry
where the IJN in all likelihood doesn't give a s**** what the IJA's problems at Guadalcanal are.

An interesting theory with regards to the rivalry between the IJA and the IJN - however, I must
point out that, quoting the much maligned Wikipedia :

https://en.wikipedia.org/wiki/Guadalcanal_campaign

The Imperial Japanese Navy (IJN) had occupied Tulagi in May and had constructed a seaplane base
nearby. Allied concern grew when, in early July, the IJN began constructing a large airfield at Lunga Point
on nearby Guadalcanal – from such a base Japanese long-range bombers would threaten the sea lines of
communication from the West Coast of the Americas to the populous East Coast of Australia. By August,
the Japanese had about 900 naval troops on Tulagi and nearby islands and 2,800 personnel (2,200 being
Korean forced laborers and trustees as well as Japanese construction specialists) on Guadalcanal. These
bases would protect Japan's major base at Rabaul, threaten Allied supply and communication lines and
establish a staging area for a planned offensive against Fiji, New Caledonia and Samoa (Operation FS).
The Japanese planned to deploy 45 fighters and 60 bombers to Guadalcanal. In the overall strategy for
1942 these aircraft would provide air cover for Japanese naval forces advancing farther into the South
Pacific.

Thus it can be seen that the Guadalcanal Operation, from the Japanese standpoint, was an IJN operation,
and the Mikawa's attack was an attempt to relieve the forces there, much like the aborted attempt
in December, 1941 by the USN at Wake was an attempt to support the USMC on Wake Island.

It is a point of fact that the vast majority of the Japanese aircraft used in the fighting over Guadalcanal
were, in fact, IJN aircraft.


Respectfully :

Paul R. Ward

Just as a Side Note: Many, MANY years ago, before ANY of you were born..... I participated in a Naval
Wargame with players from what would later morph into Silicon Valley Naval Wargamers, and S.F.B.A.N.G.,
in which we re-fought Savo with the old, unmodified Fletcher Pratt Rules. It took an entire day - and
the IJN basically slaughtered the USN, and then had a happy hour of target practice against the transports
and APDs - only two USN DDs and two APDs escaped the carnage to tell the tale. I commanded the two
DDs, and the ONLY reason I survived is because, after all the Allied cruisers and most of the DDs had been
destroyed, I decided that ' Discretion is the Better Part of Valour ' and fled eastward with the two APDs
following me, all of us laying smoke in the darkness.

The IJN would have hunted us down and finished us off, but they were overwhelmed with a sense of Pity.....
as one of the IJN players told me, " It's a PITY we've run out of ammunition...... "

[Takao]

This is reinforced by the IJN - IJA rivalry where the IJN in all likelihood doesn't give a s**** what the IJA's problems at Guadalcanal are.

Huh? This is strictly an IJN matter. The only Japanese troops involved are the 3rd Kure SNLF(naval troops) on Tulagi, and the 5th Yokosuka SNLF(naval troops) on Guadalcanal. No Japanese Army troops are involved...Yet.

[T. A. Gardner]

This is reinforced by the IJN - IJA rivalry where the IJN in all likelihood doesn't give a s**** what the IJA's problems at Guadalcanal are.

Huh? This is strictly an IJN matter. The only Japanese troops involved are the 3rd Kure SNLF(naval troops) on Tulagi, and the 5th Yokosuka SNLF(naval troops) on Guadalcanal. No Japanese Army troops are involved...Yet.

My mistake. But I'd still say that the thinking would be Nine transports...? Maybe 2000 American troops on the island... This is where the poor Japanese intelligence estimates would lead to wrong decisions and conclusions being made about what was necessary to retake the island.

[paulrward]

Hello All :

#25 by T. A. Gardner » 12 Jun 2022 16:13
My mistake. But I'd still say that the thinking would be Nine transports...? Maybe 2000
American troops on the island... This is where the poor Japanese intelligence estimates
would lead to wrong decisions and conclusions being made about what was necessary to
retake the island

Perhaps the poor performance by the USMC on the first two days of their occupation of Guadalcanal
had something to do with the underestimation of their strength.

Essentially, the IJN forces on Guadalcanal were some 2800 men, of whom some 2200 were Korean
laborers and Japanese construction troops, much like the SeaBees. Only some 600 could be termed
Combat Troops.

The U.S. attacked Tulagi and Florida with some 3000 Marines, against less than 900 IJN troops, the
fighting took two days, but the Japanese were finally wiped out.

In contrast, some 11,000 Marines landed on Guadalcanal under Vandegrift, and after driving the
Japanese forces, whom they vastly outnumbered, away from the airfield that was under construction,
instead of following them into the jungle to eliminate them, they spent the next two days unloading
supplies, setting up a defensive perimeter, and contracting dysentery and malaria ! In effect, by
not taking offensive action, they made themselves seem weaker than they were.

The Japanese forces, who had fled into the jungle with their radios, must have felt that, since the
Marines did not press the attack, they were not particularly numerous, and so might be easily defeated
by two or three thousand Japanese troops. They sent this information to Rabaul, and the Japanese
chose to act on it.

Throughout the Campaign, the IJN was limited in Sealift capacity, and so could only put forces onto
Guadalcanal in drips and drabs. The Japanese NEVER outnumbered the Marines, and for large periods
of time, the U.S. forces outnumbered the Japanese by nearly two to one. Yet, it took until the
beginning of February, 1943, or some seven months, for the island to be taken.

Respectfully ;

Paul R.Ward

[T. A. Gardner]

Well, on that I'd say part of the reason the US didn't make more effort to take the entire island was due to the overall planning the US was doing with regard to what Guadalcanal and the surrounding islands was to be. This was the US's, and particularly the USN's first forward base in the Pacific. Over on Tulagi and Florida islands--uncontested after the initial assault--the USN set up a seaplane base, a repair base, a landing craft repair and docking facility, facilities for four squadrons of PT boats. That is, they built a full naval base there.
Then other islands like the Russell's were taken to support more base facilities even while fighting on Guadalcanal continued. All of this was to provide the forward base for the next island hop which went to Funafuti atoll and that provided the jump off point for the invasion of Tarawa.

So, in a real sense, the US simply let the Japanese on Guadalcanal wither on the vine as they were increasingly bypassed and cutoff from Japan and resupply.

[Takao]

The Japanese military attache in Moscow sent a report that the US had only about 2,000 Marines on Gualcanal.
https://apps.dtic.mil/sti/pdfs/ADA313107.pdf
Source is #29.

This is also mentioned in Tameichi Hara's JAPANESE DESTROYER CAPTAIN.(although no source is given)

[Carl Schwamberger]

Hello All :

#25 by T. A. Gardner » 12 Jun 2022 16:13
My mistake. But I'd still say that the thinking would be Nine transports...? Maybe 2000
American troops on the island... This is where the poor Japanese intelligence estimates
would lead to wrong decisions and conclusions being made about what was necessary to
retake the island

Perhaps the poor performance by the USMC on the first two days of their occupation of Guadalcanal
had something to do with the underestimation of their strength.

It was lack of knowledge of the terrain. The coastal strip was known to be commercial coconut groves and subsistence farms, connected by a network of well used paths and a sort of unpaved coastal road. The assumption was this extended inland further than it did. Mt Austen was a first days objective for the landing force. The battalions assigned to it found the terrain dense vegetation with no useful paths and no fords over the streams, and a number of swamps not identified on maps or in the air photographs. Vandigrift quickly changed the plan and concentrated on consolidating the position at the airfield. That course was reinforce after the transport force withdrew and reinforcement postponed indefinitely. He had fewer combat battalions than anticipated, a large portion of the 11,000 ashore being service companies for the air wing, and other service units like the amptrack unit and the shore party battalion.

[T. A. Gardner]

The US was unsure about the terrain and even the offshore navigation obstacles in the Solomons as there were few maps of the area available. One of the ships sent to Guadalcanal was the USCGS Oceanographer (AGS-3) whose job it was to produce accurate navigation maps of the waters around the island.



I would assume the Marines were accompanied by a CB detachment that did the same sort of surveying on the island itself.

It would make sense that the Marines, particularly after the Navy defeat at sea, would concentrate on defense rather than extending themselves. They did have good engineering support from CB units though. For example, there were sawmill detachments on both Florida and Guadalcanal islands to make lumber which helped not just with structures but in building field fortifications.