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$Unique_ID{USH01475}
$Pretitle{128}
$Title{The Amphibians Came to Conquer: Volume 2
Chapter 21A The Nut Cracker: Saipan - Tinian - Guam}
$Subtitle{}
$Author{Dyer, VAdm. George C.}
$Affiliation{USN}
$Subject{pacific
japanese
marianas
saipan
admiral
amphibious
fleet
islands
general
guam}
$Volume{Vol. 2}
$Date{1973}
$Log{}
Book: The Amphibians Came to Conquer: Volume 2
Author: Dyer, VAdm. George C.
Affiliation: USN
Volume: Vol. 2
Date: 1973
Chapter 21A The Nut Cracker: Saipan - Tinian - Guam
As was stated earlier, Rear Admiral Turner remained at Kwajalein Atoll
until the capture of Eniwetok Atoll had been completed and the garrison forces
were readying to take over. He departed in his flagship, Rocky Mount, for
Pearl Harbor on 25 February 1944, entering that port on 3 March 1944. During
the long, long month commencing on 5 February, he had been sitting on the
anxious seat waiting for his promotion to Vice Admiral to be approved by the
United States Senate, and more than a bit disturbed by the backstairs gossip
surrounding the delay. The hard-fought assaults on Kwajalein and Roi-Namur,
and then on Engebi, Eniwetok and Parry, combined with this backlash had worn
him down to a nubbin.
In an off-hand remark to me he said:
When I came back from the Marshalls, I was dead tired. I stayed dead tired
for the rest of the war.
When this remark was mentioned to Fleet Admiral Nimitz, he leaned back in
his chair, his weathered face wreathed in a soft smile, and he spoke softly:
Kelly was operating under a forced draft. There were times during this period
when I wanted to reach out and shake Kelly. But Spruance always said: 'Let
me handle him' and handle him he did.
I always attended rehearsals that were held in the Hawaiian Islands. Kelly
had a firm hold on rehearsals and did a magnificent job. His insistence on
rehearsals was a major factor in his success.
And then after a pause, Fleet Admiral Nimitz, the Grand Old Man of the
Pacific War, added:
I became very much attached to him.
It must be added in all honesty that from this period in the war on, an
ever increasing number of old shipmates were aware that Kelly Turner was
partaking more freely of the liquid that cheers, but all reports indicated
that he was handling it extremely well.
The Overall Problem of Defeating Japan
As Admiral Turner said in 1949 in a speech before the General Line
School:
To defeat the Japanese, we had long recognized that we must plan ultimately
either to invade the home islands or else destroy their armies in Manchuria
and North China, and then isolate the home islands by blockade. We also
needed to weaken their industry by strategic air bombing in order to reduce
their logistics potential at home. Thus it was necessary for us to
concentrate large military forces, land, sea, and air, plus heavy stocks of
material in bases reasonably close to Japan. In turn, that meant that we
required large land deployment areas and large harbors in the Western Pacific
Ocean . . . .
The only possible suitably adequate areas were the Philippines, Formosa and
China, and of these the Philippines was much the best . . . .
Planning for the Pacific War
Out of the Sextant American-British Conference ending at Cairo, Egypt, on
6 December 1943, came the necessary approved plan to conduct the war against
Japan throughout 1944.
The Combined Chiefs of Staff and our own Chiefs of Staff never lacked for
suggestions or recommendations from the Pacific or the Southwest Pacific
commands as to how the war against Japan might be won. And frequently they
received contrary recommendations from Admiral Nimitz and General MacArthur.
In December 1943, the scales were tipped very lightly in favor of doing
what Admiral Nimitz recommended.
The Combined Chiefs of Staff, acting in accordance with the
recommendations of our Joint Chiefs, did not decide against General
MacArthur's plan of advance along the New Guinea-Netherland Indies-Philippine
axis. In fact, they decided that one advance would be made along this
north-south line toward Japan and another advance would be made along an
east-west line passing through the Marianas. The two lines of advance they
hoped would be mutually supporting during the early phases. The Joint Chiefs
of Staff decided that when conflicts over resources occurred, the Central
Pacific Campaign would have priority over the Southwest Pacific Campaign,
primarily because it held greater promise of a more rapid advance toward Japan
and her essential lines of communication with the south to bring natural
resources into the homeland.
Based on these high level decisions, Admiral Nimitz promulgated his
Granite Plan. This covered the prospective operations against the Japanese in
the Central Pacific Ocean Area during 1944.
As desired by the Joint Chiefs of Staff, the Marshall Islands would be
assaulted early in 1944, with Eniwetok being taken about 1 May 1944. About 15
August, the Mortlock Islands (160 miles southeast of Truk) and Truk Atoll in
the Carolines would be taken. Then, about 15 November 1944, Saipan, Tinian,
and Guam would be assaulted simultaneously, if possible.
All during this period, Admiral King held to the firm opinion that the
Marianas were the key to the Western Pacific since, from the Marianas, we
could quite easily cut the Japanese line of communications to the Netherland
East Indies and Malaysia and from there could bomb Japan.
Admiral King also believed that reaching the mainland of China was a
major objective of the drive through the center of the Pacific Ocean. This
was in order to take advantage strategically, not only of China's geographical
position but of her huge manpower.
Two things happened in the first seven weeks of 1944 to change the
strategic picture further in our favor.
1. The Japanese Combined Fleet retreated from Truk Atoll to the Palau
Islands in the Western Carolines.
2. Eniwetok was taken in late February, rather than in early May.
Admiral Nimitz, soon after Eniwetok was firmly in hand, wrote to the
Commander in Chief, United States Fleet:
The capture and consolidation of Kwajalein, Majuro, and Eniwetok, together
with the successful Fleet operations against Truk and the Marianas, have
created changes in the strategic situation which permits advancing the timing
of operations contemplated by the Granite Plan.
In a long reasoned discussion, Admiral Nimitz then developed two proposed
schedules of future operations, one in which Truk would be assaulted 15 June
1944, with the Southern Marianas assault to follow on 1 September 1944. The
other schedule called for Truk to be neutralized and bypassed, and the
Southern Marianas to be assaulted on 15 June 1944. Subsequently, Woleai, Yap
and the Palaus (about 1060 miles southeast of Manila) were to be captured by 1
November 1944 (later changed to 1 October)
Admiral Nimitz believed that following the latter schedule, which
advanced the assault date on the Marianas by two and a half months, would
permit readiness of his forces in the Pacific Ocean Areas to launch a major
assault in the Formosa-Luzon-China area in the spring of 1945.
While awaiting the decision by Admiral King and the Joint Chiefs of
Staff, Admiral Nimitz's Staff would not be idle. The Admiral wrote Admiral
King that: "Plans are being drawn up and forces prepared for either objective
[Truk or the Southern Marianas]."
It should be recorded here that there was some naval opposition and
considerable lack of enthusiasm for the operation to take the Southern
Marianas. This arose because of the complete inadequacy of the harbors in
Saipan and Tinian and the limited capacity of Apra Harbor, Guam. For a
satisfactory mobile logistic support base in this general area it would be
necessary for the Pacific Fleet to go 400 miles southwest of Guam to Ulithi
Atoll in the Western Caroline Islands. Eniwetok had a fine anchorage, but the
rim islands were all too small for the development of shore-based storage and
work shop activities. Moreover, it was located a thousand miles back towards
Pearl Harbor from the Marianas.
Admiral Nimitz's letters to COMINCH and later visits to Washington were
occurring against a background of strong urging by General MacArthur during
January and February 1944, to do something quite different with the naval
forces of the Central Pacific.
In early February 1944, General MacArthur was pressing for the commitment
of large combatant Pacific Fleet forces on a long continuing basis to support
his advance toward the Philippines. In a despatch he said:
I propose that with the completion of the operations in the Marshalls, the
maximum force from all sources in the Pacific be concentrated in my drive up
the New Guinea coast to Mindanao, to be coordinated with a Central Pacific
Operation against the Palaus and the support by combatant elements of the
Pacific Fleet with orders to contain or destroy the Japanese Fleet.
Despite the firm decision of the Combined Chiefs and the Joint Chiefs of
December 1943, that the Central Pacific campaign would have priority, General
MacArthur sought to advance his own proposals by sending his Chief of Staff
and supporting officers to Pearl Harbor, and then on to Washington.
Admiral King thought that the proposal to divert major naval resources
from the Central Pacific to the Southwest Pacific on a long time basis was
"absurd" and so said to anyone within hearing and in a letter to Admiral
Nimitz.
On 2 March 1944, the Joint Chiefs avoided meeting the issue head on, but
did go so far as to state:
Our first major objective in the war against Japan will be the vital
Luzon-Formosa-China coast area.
This tied in with the Central Pacific Campaign far more realistically
than the south-north drive up through New Guinea, particularly when coupled
with a Joint Chiefs' cancellation of General MacArthur's proposed assault on
Kavieng in New Ireland, and advice to him that the Central Pacific Campaign
had priority in military resources over the Southwest Pacific Campaign.
It was another ten days before the seal of approval to the Central
Pacific Campaign and the Granite Plan was reaffirmed.
The final Joint Chiefs' decision was to confirm Admiral Nimitz's proposal
to assault the Marianas on 15 June 1944. Success in the Marianas, of itself,
would largely neutralize Truk and isolate the Central Carolines because it
would throttle the main Japanese aircraft pipeline down from the Empire to the
Carolines. The Palaus in the far western Carolines would be assaulted on 15
September 1944, with the object of establishing a fleet base there, as well as
a forward staging area for later operations against Mindanao, Formosa, and the
China coast. If all went well, Mindanao would be assaulted on 15 November by
General MacArthur, supported by the Pacific Fleet, and Luzon or Formosa would
be assaulted on 15 February 1945. The object of taking Mindanao was to
further the advance to Formosa either directly or via Luzon.
The JCS directed that long-range planning be undertaken for assaults on
all three objectives - Luzon, Formosa, and the China coast area - with General
MacArthur's Staff undertaking the first, and Admiral Nimitz's staff the latter
two.
The Purposes of the Exercise
The code name of Forager was assigned to the capture, occupation, and
defense of Saipan, Tinian, and Guam.
The Commander in Chief, Pacific had four principal purposes in mind in
launching Forager. The obtaining of an island base from which the Japanese
homeland could be bombed was the one appealing to all Services, although more
strongly to the Army Air Force, since it would permit them to really pull an
oar in the Pacific War. A second principal purpose was to obtain a base which
would permit the isolation and neutralization of the Central and Western
Carolines. This one appealed particularly to the Army as it was anxious to
facilitate General MacArthur's movement to the Philippines, and this would be
made more practical if, as he advanced, Japanese island positions on his right
flank were isolated or neutralized. The other two principal purposes were
primarily naval. The Navy thought it was highly desirable to have effective
command of the sea in the general Marianas area, and thus a forward position
on the flank of the Japanese communication lines to the Philippines and
Southeast Asia. This was in order to harass or break these Japanese lines of
communication. There also was a strong naval desire to secure a large base
from which a direct amphibious assault could be launched against the Ryukyus,
the Bonins, or the Japanese Homeland.
The Nut Cracker
A glance at the detailed chart and maps of Saipan, Tinian and Guam
immediately indicates that the Marianas were quite a different cup of tea from
Makin or Tarawa or Kwajalein or the other atolls which had been captured in
1943 and early 1944. Rather than small flat rims of coral, they were good
sized islands with all the defensive possibilities which real fortification,
rough terrain and tropical growth over large land masses can provide.
And it is worth stating a second time that with the Marianas located over
3,000 miles from Pearl and something less than half that far from Tokyo, it
would be far more difficult to establish there the prerequisites for a
successful amphibious operation. These are:
1. Secure lines of communication to the zone of conflict.
2. Command of the seas around the objective.
3. Command of the air around the objective.
It has to be kept in mind that an invader is most vulnerable as he hits
the beaches. This is the transition period of an amphibious assault.
Resources
Three divisions, which had been earmarked for the sequential assaults on
the Mortlock Islands and on Truk, were designated for the invasion of Saipan
and the subsequent capture of Tinian. These were the Second and Fourth Marine
Divisions, with the 27th Infantry, a National Guard unit from the State of New
York, in reserve. They were to be mounted in the Hawaiian Islands, 3,000
miles away.
For the assault on Guam, the Third Marine Division and the 1st
Provisional Marine Brigade, made up of the 4th Marine Regiment, the 22nd
Marine Regiment, and, after 10 July 1944, the 305th Infantry Regiment, were
assigned. The units initially assigned were designated the 3rd Amphibious
Corps on 15 April 1944, Major General Roy S. Geiger, USMC, Commander. They
were to be mounted in Guadalcanal and the New Hebrides, 1,650 to 2,200 miles
southeast of Guam. The 77th Infantry Division, training in the United States
during the early planning period, was to be brought to the Hawaiian Islands by
March, and alerted for a move on to the Marianas twenty days after Dog Day at
Saipan. It could not be mounted for a Dog Day assault or as the Guam Reserve
because of lack of transports and cargo ships. From this listing of
participating troops, it is apparent that the Marianas was to be the biggest
amphibious assault to date in the Central Pacific Campaign with three and
two-thirds divisions designated for assault and two divisions designated for
the Reserve.
Forager, the Marianas campaign, was complicated. As Admiral Turner said:
The Marianas Campaign, from an amphibious view point had nearly everything;
great strategic importance, major tactical moves including successive troops
landings on three enemy islands; tough enemy resistance of all kinds,
including major Fleet battle; coordination of every known type of combat
technique of the land, sea, and air; difficult logistic problems; and the
build up of a great military base area concurrently with the fighting.
Before the operational phases of the Marianas campaign are related, a few
of the major changes in the administrative and organizational aspects of the
Amphibious Forces, Pacific will be set down.
Ships and Landing Craft and More Ships and More Landing Craft
COMINCH, on 1 February 1944, assigned all attack transports, attack cargo
ships, and landing ships and craft, in or destined to report to the Pacific
Ocean Areas, to Commander Amphibious Forces, Pacific (Rear Admiral R. K.
Turner). This broadened his command from the Fifth Amphibious Force in the
Central Pacific to all the amphibious forces in the Pacific Ocean Area. On 8
March 1944, Vice Admiral Turner reported to CINCPAC for this additional duty
which included command of all amphibious craft assigned to the First, Third,
Fifth, and Ninth Fleets; the Amphibious Training Command; and the Army, Navy,
and Marine Corps units currently assigned to those Amphibious Forces for
training or combat operations. He was also responsible for the preparation
and periodic correction of two Pacific Fleet publications entitled Tactics
Orders, Amphibious Forces, Pacific Fleet and Current Doctrine for Amphibious
Forces, Pacific Fleet.
As the Amphibious Forces moved through the Gilberts and the Marshalls,
some of the landing ships (LST's) and many of the landing craft (LCT's) were
left behind to provide the necessary unloading lighterage at the island bases.
There was a real need to reorganize the landing ships and craft which returned
to Pearl with sizeable gaps in their organizations and provide appropriate
division commanders, group commanders and flotilla commanders. The need was
brought to the attention of CINCPAC and COMINCH, and the latter, on 30 March
1944, authorized remedial action. Thereafter, COMPHIBSPAC, acting under
delegated authority, reorganized the LST's, the LCI's and the LCT's, generally
on the basis of geographical location. This, as many skippers were quick to
report, broke up many fine chains of command which had existed since the
landing ships and craft were on the building ways back in the States. Soon
afterwards, a more favorably-received step was taken. This was to provide
adequate repair facilities for these craft even in the forward areas.
In early April 1944, the first edition of Transport Doctrine, Amphibious
Forces, U.S. Pacific Fleet was issued. This healthy sized document provided
general transport doctrine as well as specific transport doctrine for all
types of landing ships and landing craft. It was amended a dozen times before
World War II was over, but it served to indoctrinate the tens of thousands of
young Americans who were becoming amphibians.
The Fifth Amphibious Force Staff Grows and Grows
By the time the Fifth Amphibious Force was deep in its training to take
the Marianas Islands, Vice Admiral Turner's Staff had grown to thirty
officers. The number of officers attached to the staff for communications,
intelligence and other specialty duties had increased to 56. The Chief of
Staff had been advanced in rank to Commodore early in April 1944.
Kneeding Flintlock into Forager
Although Flintlock was termed a grand success, COMFIFTHPHIBFOR issued a
37-page letter, with comments on the operation and many suggestions for
further improvements in the naval phases and naval techniques of the
amphibious operations.
On the other hand, the Commanding General, V Amphibious Corps, was
reasonably satisfied, as this extract from his report indicates:
Recommendations made and acted upon - as a result of the Gilberts offensive
proved sound. In the attack of coral atolls, very few recommendations can be
made to improve upon the basic techniques previously recommended and utilized
in the Marshalls.
From the time of the conquest of the Marshalls, the DUKW was the major
small logistical workhorse of the Central Pacific Campaign, and as Admiral
Turner commented:
The Army's most important contribution to the technique of amphibious warfare.
The Marianas
The Marianas are a 450-mile long string of fifteen volcanic islands lying
north and south between Latitudes 13 and 21 degrees north, and generally along
the 145th parallel of east longitude.
Guam is the southernmost of the island string. It lies a bit less than
1,400 sea miles south-southeast of Tokyo and 1,500 sea miles east of Manila.
101 miles separate Saipan, the second largest of the Marianas, from Guam.
Tinian nestles up to Saipan and Rota is 37 miles northeast of Guam. Eleven
smaller islands stretch 350 miles north of Saipan.
Guam also is the largest of the Marianas, with a land area of 206 square
miles. Saipan covers 70 square miles and Tinian only 38 square miles. Each
of these three islands has both rock-ribbed hills and swampy valleys. Guam
has half a dozen rugged peaks over a thousand feet high with the highest being
Mount Lamlam of 1,334 feet. Saipan tops out in its center at Mount Tapotchau
at 1,554 feet, while smaller Tinian, in general, is flatter with Lasso Hill of
564 feet its highest point. Tropical vegetation, in 1944, covered much of the
islands, and there were marshes and rice paddies in the lowlands. The only
useful harbors in the group are Apra Harbor in Guam and at Tanapag in Saipan.
The latter is very small. The tide in the Marianas is negligible since it is
less than 1.5 feet.
Raising sugar cane, copra, bananas, and papayas were the principal
activities of the natives in 1944. Seventy percent of Saipan was under sugar
cultivation. The population of Saipan and Tinian was principally Japanese
with a modest proportion of Chammorro's, while that of Guam was entirely
Chammorro.
Natural Defenses
Saipan
Looking at the three principal southern islands in 1944 from the
amphibious assault viewpoint, it was seen that a barrier reef one to two miles
off shore protected the west side of Saipan. The land sloped gently away from
the beaches which were extensive but only 10 to 15 yards wide. On the east
side, the beaches were narrow and the shores steep with many wave-cut cliffs.
The north end and east side of Saipan, except for Magicienne Bay, were free of
reefs. This bay provided no shelter from the prevailing trade winds and the
Japanese, reputedly, had not used the bay because of this and the inshore
reefs.
Tinian
Tinian had the same natural defenses as Saipan's east coast - healthy
sized cliffs and very narrow shallow beaches. This would make the logistic
support problem very difficult in the early hours of any assault landing.
Guam
The detailed information available during the 1944 planning period in
regard to the beaches of Guam was good, because the Marines had studied the
island from a defensive point of view during the pre-1941 period. The
northern half of the island was easily defendable because of the high cliffs
overlooking the beaches and the strong surf and rugged offshore reefs. The
868 Amphibians Came To Conquer
whole east coast of Guam was marked by a 400-foot plateau and a narrow coastal
flat. However, in the vicinity of Agana Bay near the capital Agana, there
were some breaks in the long reefs on the western side of the island, and
another break south of Orote Peninsula. This peninsula jutted out three miles
into the western ocean and provided a lee for the beaches south of it.
The Weather Prospects
In a few words, the weather was warm, showery and generally overcast.
The summer months are the rainy season, August being the wettest month with
numerous thunderstorms and squalls.
Typhoons are scarce around the Marianas but do occur. The monsoon winds
blow in from the southwest in August and September; the trade winds blow from
the northeast the rest of the year.
So, from a weather point of view, the landings and early logistic support
follow up had to be completed before the end of July, if the landings were to
be made on the west coast of Saipan where the preferred beaches were located.
The "generally overcast" type of weather meant that air reconnaissance would
have photographic and observation problems.
Japanese Reaction to Loss of Marshalls
Admiral Koga, Commander in Chief of the Japanese Combined Fleet, made a
visit to Japan from Truk soon after our seizure of Kwajalein and Eniwetok in
the Marshalls, to Participate in military conferences. The Japanese High
Command on 1 March 1944 took the decision to build up overseas personnel and
material strength, construct fortifications with special emphasis on the
Marianas and Western Carolines, and firmly defend their new "Secondary Defense
Line." These important defensive steps were planned to be completed by April
1944, and except for planned aircraft and air bases they were largely in hand
by the end of May 1944.
A Japanese Central Pacific Area Force secret order captured during the
Forager Operation indicated that, in the Marianas, Japanese plans contemplated
a total of fourteen airfields and two seaplane bases adequate to handle 600
aircraft. In the Southern Marianas, by early June 1944, there were two
Japanese airfields operational on both Saipan and on Guam, three operational
airfields on Tinian and a surfaced runway on Rota. Additional airfields were
in various stages of completion. There was a major Japanese seaplane base at
Tanapag Harbor on Saipan.
The Japanese Defenses
Soon after arriving back in Pearl, and still not sure whether the next
amphibious objective would be Truk or the Marianas, COMFIFTHPHIBFOR requested
CINCPAC to provide air and submarine reconnaissance of the Carolines and
Marianas to supplement that obtained on 22-23 February 1944, during the first
air strikes against the Marianas.
This was done by Navy PBYs, flying out of Eniwetok on 18 April and 25
April 1944, and again on 7 May and 29 May 1944. The submarines of the Pacific
Fleet during April 1944 gave their particular attention to prospective landing
beaches with rewarding results.
The Japanese on Saipan
The natural defenses of Saipan, the first island in the Marianas to be
assaulted, were considerable. The east coast was largely free of fringing
reefs except around the largest bay - Magicienne Bay - but the beaches were
narrow - and more importantly from the Marines' point of view - the shores
back of the beaches were steep, rugged and easily defended.
The west coast of Saipan was lower and the land back of the beaches
sloped gently upward, which was fine from the Marine point of view. But, with
the exception of a gap off Charan Koa and the entrance to Tanapag Harbor, a
barrier reef protected the whole west coast of Saipan.
On Saipan the Japanese had an island 12 3/4 miles long and 5 3/4 miles
wide to defend. In comparison, the later objectives, Tinian was 10.5 miles
long and markedly narrower than Saipan, while Guam was 32 miles long and 4 to
8 miles wide.
Beginning in March 1944, the Japanese not only rapidly built up their
defenses and their defensive forces in the Marianas, but, additionally,
reorganized the command structure which controlled the area.
The Fourth Fleet which had held the bag during the loss of the Gilbert
Islands and the Marshall Islands was downgraded to controlling only the naval
garrisons in the Eastern Carolines (including Truk) and the bypassed
garrisons in the Marshalls, all of which were dying on the vine. A new
command directly under the Combined Fleet, called the Central Pacific Area
Fleet, was established under the command of Vice Admiral Chuichi Nagumo, IJN,
who had been commander of the Japanese naval force making the surprise attack
on Pearl Harbor. Vice Admiral Nagumo maintained his Headquarters on Saipan
and was present and accounted for when the assault commenced. He controlled
the naval garrisons in the Western Carolines where the important Palau Islands
were located, as well as the Marianas and the Bonins where Iwo Jima was
located. The responsibility for the defense of individual islands rested upon
the senior Army or Naval officer assigned to that island. By and large, the
Japanese Army was able to place the senior officer on each island.
Saipan also housed the Japanese Army command for all Japanese Army forces
in the Mandates. This was the 31st Army. Its Commanding General was
Lieutenant General Hideyoshi Obata. He lived a few days longer than others
because he was absent from his command and in the Palau Islands for a
conference when we landed 01115 June 1944. His senior subordinate, Lieutenant
General Yoshitsugu Saito, IJA, Commanding the 43rd Division, took over Obata's
duties and fought the good fight.
All during the months of March, April, May, and early June, the Japanese
poured troops into the Marianas. They had their troubles doing this as the
following extract from an interrogation of Commander Tadao Kuwahara, IJN
(Retired), Convoy Commander for part of the movement of the 43rd Division,
will show:
I left Tateyama for Saipan on 30 May 1944 with a convoy of seven vessels and
four escorts. Three of the ships were transporting 10,000 troops to Saipan.
This was the last convoy to go to Saipan . . . . The convoy was attacked by
submarines on the 1st through the 6th of June, all attacks occurring at about
1500-1600. The submarines had been following another convoy bound for Japan.
When the two convoys crossed, the submarines turned around and followed my
convoy . . . . On 4 June, the convoy was attacked simultaneously from the two
front quarters and the port after quarter. Katsuya Maru was sunk. On 5 June,
we were attacked again from two sides and Takaoka Maru and Tamahime Maru were
sunk. On 6 June we were attacked once more on two sides, simultaneously.
Kashimaran Maru, carrying aviation gasoline was hit during this attack and
exploded. About an hour later, another attack sank Haore Maru. Of the troops
of the three troop transports . . . 80% were saved . . . .
Eighty percent of the Japanese troops of this particular movement were
saved but their heavy equipment including guns and ammunition were all lost.
As was reported by despatches from Saipan to Japanese Headquarters in
Tokyo:
The shipwrecked units are 3rd and 4th Independent Tank Companies, 14th and
17th Independent Mortar Battalions, 3 aviation units, etc., and have no use as
fighting units; the infantry are without hats and shoes and are in confusion.
And, while the Japanese rapidly built up the defenses of Saipan, there
was much they didn't do. The Commander in Chief, Pacific Ocean Areas in his
Operational Report on the defenses of Saipan, based on data determined after
the occupation, wrote:
Subsequent to the capture of Saipan, an inspection of its defenses was made by
the Engineering Section of the Expeditionary Troops. Information was obtained
from an important prisoner of war who had been the former Intelligence Officer
of the Japanese 43rd Division and from captured documents . . . .
The prepared defenses of Saipan were amazingly inadequate and incomplete
. . . . Not a single battery position or fortification inspected was entirely
complete . . . . In the Garapan Naval Depot, the following guns were found:
3 5" coast defense guns, 1 140-mm coast defense gun, 32 120-mm dual purpose
guns, 6 200-mm mortars.
Guns implaced ready to fire:
6" 120-mm 200-mm Total
8 20 4 32
* * * * *
It can be seen that only slightly more than one-third of the heavy coast
defense and dual purpose guns that were available on the island had been
completely mounted and made ready for firing.
Japanese Defense Doctrine
The Japanese documents captured in previous amphibious operations had
always stressed the Japanese island defense doctrine of "destroying the enemy
at the beaches," or in other words during the most difficult period of the
amphibious operations - the transition period from naval war to land war. It
was widely anticipated that since the Marianas were quite different islands
than those in the coral atolls, that the Japanese defensive pattern would
change. But it didn't. A captured document on Saipan read:
It is expected that the enemy will be destroyed on the beaches through a
policy of tactical command based on aggressiveness, determination and
initiative.
The Japanese Fleet Again Retires Westward
When Task Force 58 raided the Palau Islands at the end of March 1944, the
Japanese Combined Fleet once again retreated westward, this time to Tawi Tawi
Harbor in the Sulu Archipelago in the Southwest Philippines. It was operating
in this area, 1,600 miles away from the Marianas, when the Joint Expeditionary
Force moved in to assault the Marianas.
Worried about the defense of western New Guinea, a good sized detachment
of the Combined Fleet was under orders early in June 1944 to support a
Japanese amphibious assault to recapture Biak Island off northwestern New
Guinea. Japanese land-based planes from the Marianas were ordered down south
to Halmahera to support the operation. The Japanese task force for this
assault, Operation KON, was actually well assembled at Batjan in the Moluccas
(southwest of Halmahera, four hundred miles south of Mindanao) by 11 June.
Reports of the TF 58 raids on the Marianas late on that day raised doubts
in the minds of the Japanese as to whether the Marianas were being raided or
whether they were a United States amphibious assault objective. Upon receipt
of news on 13 June that battleships were bombarding Saipan, the Japanese
assault on Biak was cancelled by Admiral Toyoda, Commander in Chief Combined
Fleet. He had succeeded to command the Combined Fleet upon the death in a
plane accident of Admiral Koga. The cancellation was the the first of many
pleasant dividends from Forager.
Organizing for Forager
The tremendous size of the Forager Operation began to become a reality
when the Commander Pacific Ocean Areas in his basic order directed:
All major Commanders in the Pacific Ocean Areas will support this operation.
To give further orientation on the titular nomenclature used in the
Central Pacific it should be recorded that when Admiral Spruance was directed
to conduct the wide-ranging Forager Operation it was as Commander Fifth Fleet
rather than as Commander, Central Pacific Task Forces.
The Expeditionary Troops included the two Landing Forces, each
approximately the equivalent of a corps command, as well as the Expeditionary
Troop Reserve and the Garrison Troops. Lieutenant General Smith retained
command of the Northern Landing Force, but in this task used a staff separate
from the one which functioned with him in the whole Expeditionary Troop
command. Major General Roy S. Geiger, USMC, commanded the Southern Landing
Force at Guam.
The two assault Landing Forces initially totaled 127,500 men, with 71,000
for Saipan and 56,500 for Guam.
Commander of the Saipan troops in the Expeditionary Reserve (CTG 56.3),
the 27th Infantry Division, was Major General Ralph Smith, AUS. Major General
Andrew D. Bruce, AUS (CTG 56.4), commanded the 77th Infantry Division,
initially designated "In general area reserve" but planned to be used for the
Guam landings.
As it turned out, the "general reserve" was embarked from Pearl Harbor in
two echelons based on the availability of transports. Captain J. B. Heffernan
(1917) embarked the first echelon, the 305 Regimental Combat Team from the
77th Division, in a division of transports on 2 July, and Captain H. B.
Knowles (1917) embarked the second echelon, which was the remainder of the
77th Division in two divisions of transports on 9 July.
In the original plan it was estimated that the Joint Expeditionary Force
would complete its missions for Forager about Dog Day plus 40 (July 25th) and
that the entire movement of garrison forces and equipment would be completed
about Dog Day plus 80 (September 3rd). The first estimate turned out to have
been optimistic.