Battle of Guam

Battleof Guam


Thispaper explores the battle of Guam that took place in the 1940’s.Guam is the westernmost territory of the United States located in theMariana Islands. Earlier on, Guam was taken into possession by theUnited States immediately after the American-Spanish war that tookplace in 1898. Prior to the battle, Japan had captured the lightlydefended territory of Guam. Immediately after the advances madethrough a number of Islands including the Marshall and GilbertIslands that saw several territories such as Kwajalein and Tarawabeing secured, the allied generals started plotting for a return tothe Mariana in 1944 (Rottman, 2004). Initially, these plots hadcalled for first landings to be on Saipan and then the troops were toproceed to Guam after some few days. The landings were to be followedby aerial attacks by the United States Army Air Force. This paperwill review the tactical situation of the battle, the condition andmorale of the soldiers, and lastly the key leaders of the battle andtheir respective experiences.

Keywords:Tactical training, , Northern Troops and Landing Force(NTLF), Southern Troops and Landing Force (STLF).


Guamis the westernmost island territory of the United States, and it islocated in the Mariana Islands in the Western Pacific Ocean. Theterritory is mainly inhabited by an indigenous group of people knownas the Chamorros, who are said to have settled in the island in 2,000BC. It is the largest island in the Marianas and covers approximately225 square miles. During the 18thcentury, Guam had developed to be a significant territory of theSpanish until the Spanish-America War broke out and the territory wascaptured by the United States in 1898 (Rottman 2004). Guam iscurrently one of the territories in America with a well-establishedcivilian government. In 1941, the Pearl Harbor was under attack and,therefore, Guam was not adequately protected by the United States andthis led to attacks by the Japanese and the eventual capture of theterritory. This paper will examine the battle of Guam the tacticaldoctrine and training of the forces, the condition and morale of thesoldiers, and the key leaders in the battle and their respectivetraits, influence, and experiences.

Thecapture of Guam in December 1941 by the Imperial Japanese armedforces marked their first victory in the Pacific War. The secondbattle which was fought in July 1944 was won by the United Statesforces. In 1941, the territory was rather defenseless it was leftexposed after the attack on Pearl Harbor, it was also within thevicinity of Saipan which at the time was an important air and navalbase in Japan. There were less than 500 hundred Marine and Navypersonnel who manned the territory in addition, there wasapproximately 300 police and militia who defended Guam (Rottman,2004). Another challenge in Guam was the lack of superior weaponrythey had few machine guns and no aircrafts and fortification. Theyalso lacked reinforcement and, therefore, could not protectthemselves against the Imperial Japanese armed forces. The island wasthus taken into captivity by the Japanese.

TacticalDoctrine and Training

TheUnites States forces had earlier adopted a tactical doctrine toassist themselves in battles. The doctrine had formulated by planninggroups during the Pearl Harbor. The doctrine of the Americans wasevaluated against forces that were available for landing, followingup the process and support. Throughout the war, corps reinforced boththe brigade and division.

Takinginto account that the opposition was likely to be fierce in such away that they could contain the beachheads and prevent them fromlinking with those on the ground, this presented a huge problem tothe successful delivery of artillery. Brigadier General Pedro A. delValle together with his artillery staff strategized to include two155mm battalions just behind the brigade (Rottman, 2004). This changewas done to enable the forces to use heavier guns that are capable oflong range fire attacks. The inclusion of the two 155mm battalionsalso reinforced the marines. At the same time, the strategy wouldalso permit the 1stbattalion to maximize their short range fires.

Anotherstrategy apart from del Valle’s was General Geiger’s plan. Hegave permission to the commander in charge of artillery to overseeall artillery and antiaircraft units in the south. In this manner, itwas easier to coordinate fires with air and naval gunfire. Inaddition, the tactic would also enable the massing of gunfire on onetarget in case it required the full impact of artillery (Rottman,2004).

Aunique feature of the Southern Troops Landing Force (STLF) was thatthe first two groups would be approximately 7 miles apart from eachother. This was to trap the Japanese in the middle. It also allowedthe forces to move in case one of them was delayed by the difficultterrain or attacks by the enemy. The actual tactic was changed sincethe Japanese forces had occupied the most suitable entry points tothe island.

Thethird division was to land on the Asan Beaches in the north and Asanpoint which were both the strong points for the Japanese forces. Thepurpose of the 3rdMarines was to secure Adelup Point and later seize Bindschu Ridge(Rottman, 2004). The other Marines in the center would continue topenetrate inland. The 9thMarines had the task of seizing Asan point and then head towards ApraHarbor.

The1stProv MarBde had a task of launching an assault on the SouthernBeaches. The 22ndMarines would head north. The 4thMarines were to be followed inland by the 305thInfantry. The 305thMarines would then defend the beaches. The remaining groups of the77thInfDiv were to serve as reserves for the Southern Troops Landingforce (STLF) in the beginning but were later sent to Hawaii (Rottman,2004).

Trainingand rehearsals were conducted by the IIIAC at Guadalcanal. Only the77thInfDiv did not take part as they were still in Hawaii. The variousunits began departing on 1stJune whereby they proceeded to Kwajalein and later to Saipan.

Theassault on Guam was initially planned to take place on 18thJune but was later rescheduled for various reasons. Firstly, the 1stMobile Fleet was approaching the territory from the Philippines andhence the landing had to be delayed so as to avoid endangering theother force en route to Marianas (Rottman, 2004).

Duringthe time of planning, the ground units and the navy unit had apeaceful life and hence the commanders decided to provide intensivetraining. The Marine units were further trained on landing. A largenumber of ships had to be refitted from the past operation and at thesame time be loaded for the assault. The experienced troops andsailors had little to be taught but they still had some practice incritical areas.

Withmost of the landings expected to take place over wide coral reefs,the 3rdMarine Division conducted more training to enhance the techniquesthat were required in such situations. The 3rdmarines also carried out some experiments on the transfer of troopsand weaponry (Rottman, 2004). In addition, a number of tests werecarried out on effective ways of massing fires from the beaches.Lastly, there were studies to find out the various types of beachesin Guam and checks were made on how the troops would land on thebeaches.

The12thMarines were tasked to find out the most suitable way to employvehicles that were assigned to landing in the territory. In additionto these training, the Marines were familiarized with small-unitbattles in forested areas and in grass plains. Only the 1stProvisional Marine had a short training cycle (Rottman, 2004).

InSamoa, there was a change in tactic as a large number of troops werediagnosed with filariasis. Within a short period of time, it became anecessity to replace approximately 2,000 troops because of thedisease. There were some other casualties resulting from training,battle, and transfers than needed replacements. As a result of theinflux of inexperienced troops, the training officers, therefore, hadto intensify the training with more emphasis put on small-unittactics (Rottman, 2004).

Thefinal training of water and land elements started on 12thMay. On each day, ship-to-shore training were carried out, three ofwhich were attack groups (Rottman, 2004). This training also providedeach group with an opportunity to become efficient on landingtechniques. This was followed by exercises on air support andregimental landing. Lastly, the troops were trained on airoperations, use of live bombs and ammunitions.

Onthe Japanese side, Lieutenant-General Takeshi, who was the commanderof the 29thDivision and South Marianas Army Group, came up with specific tacticsfor defense. The 48thIMB was tasked with defending the Asan Beaches, with the 10thIMRand the 29thDivision as back-up. The 320thIIB’s main responsibility was to overlook the Asan Beaches whilethe 321ststayed on northern Agana Bay’s defense (Rottman, 2004).

TheJapanese faced shortages of small arms and infantry, inferiorweaponry, lack of reinforcement and inadequate air support,therefore, their tactical situation was bleak. The Japanese reliedheavily on the ability of the Combined Fleet to defeat the UnitedStates. However, they had to change their tactics as the UnitedStates air attacks destroyed all of their aircraft before theSaipan’s D-Day.

TheJapanese forces (31stArmy) which can be roughly equated with the United States Army Corpshad little tactical control over its several divisions. Most of thedivision’s members were green and untrained, for instance, theImperial Japanese Navy Forces had leaders and troops who did not haveany tactical training and experience they were armed with onlyassault rifles and a few machine guns (Rottman, 2004).

Conditionand Morale

Althougha number of airstrikes had been launched by the United States priorto the battle, the Japanese forces became alert on the possibleattacks by the US forces and hence they attempted to strengthen theirdefenses. The morale of the American forces before and during thebattle of Guam was positive since they had prepared very well bytraining and also had superior weaponry and enough reinforcements.The Japanese on the other hand were ill-prepared and, therefore,lacked the positive morale during the battle. In addition, theAmerican forces had destroyed all the Japanese aircraft on the D-Day.

Boththe United States Forces and the Japanese Forces had been successfulin their previous fights. The Japanese had first fought and capturedGuam which was an American territory. The Japanese attacked Guamwhich was lightly defended and they were successful in the fight. Onthe other hand, The American had just fought in the Philippines andwon prior to the battle of Guam. Soldiers from both forces believedin the cause of the fight and wanted to protect their territory. Thecombat leaders regularly reminded their soldiers the cause of thefight as a measure to improve their morale and discipline.

Theweather and the terrain of Guam had both positive and negativeeffects on the morale of the soldiers. Guam had a rugged and hillyterrain which was an impediment to movement of vehicles and soldiers.This was, however, advantageous as it could be used for hiding andmassing fire at the opposing forces. The harsh weather, however, hada negative effect on the morale of the units as some soldiers becomeill.


Oneof the key leaders of the American Forces in the battle is CaptainGeorge J. Mcmillin. He first joined the United States Navy in 1907and graduated four years later. He also attended the Naval WarCollege where he got over 15 years experience in seas duty aboardcarriers and cruisers (Rottman, 2004). In addition, he also hasexperience in sea service in Mexico, Dominica Republic, and World WarI. He also has experience at the Navy Department, Naval War College,and Naval Academy. With his wide experience, he was tactically andtechnically proficient. Cpt. Mcmillin was not very flexible to thechanging nature of the battlefield though and hence he only served inthe sea service.

Anotherkey leader of the United States Forces in the battle is Vice AdmiralRichmond K. Turner. He attended the Naval Academy and graduated in1908. He later served in the World War I. In addition, he laterchanged his career and became a Naval Aviator. Turner had a lot ofinfluence on the battle as he directed all amphibious forces. He wasalso flexible as he served in different leadership positions duringthe battle (Rottman, 2004).

Major-GeneralRoy S. Geiger (USMC) is also another key leader in the battle ofGuam. He was highly experienced in a number of areas he served as aNaval Aviator, a pilot, and an amphibious corps commander.Major-General Geiger excelled in corps operations and fire supportand was, therefore, highly influential and flexible to the changingnature of the battlefield he adapted to every situation and emergedvictorious.

Major-GeneralHorii Tomitaro (IJA) was a key leader of the Japanese army. He wasfirst commissioned as an infantry sub-lieutenant in 1911 (Rottman,2004). He was highly experienced as he held a number of positionsincluding being a battalion commander and a regimental commander.Major-General Tomitaro was very flexible to the changing nature ofthe battlefield and was tasked in commanding several forces in theisland.

Anotherkey figure in Japanese forces is Lieutenant-General Obata Hideyoshi.He was highly experienced and influential leader of the Japaneseforces as he commanded the 31stArmy. He attended the Army War College in Britain. He later tookcommand of the 31stArmy and was very influential in the battle of Guam (Rottman, 2004).He was not flexible to the changing nature of the battlefield and forthis reason lost in more battles that he fought in later years.


O’Brien,C. J. (n.d.). Liberation: Marines in the Recapture of Guam RetrievedAugust 23, 2016,


Rottman,G. L. (2004). Guam1941 &amp 1944.Oxford: Osprey Publishing