Sunday, February 3, 2013

FLINTLOCK: The Battle for Kwajalein Atoll

By Mark E. Hubbs

Most of this article came from a Kwajalein Battlefield Tour Guide that I prepared for the US Army Space and Missile Defense Command many years ago.
February 1, 2013 marks the sixty-ninth anniversary of Operation FLINTLOCK, the battle to seize the Marshall Islands from the Japanese.  Most Americans, even those who are not students of history, have at least heard the names "Iwo Jima," "Tarawa" or " Peleliu."  Few have heard of Kwajalein although it was the first Japanese owned territory, the edge of the Japanese Empire itself, that was taken during the war.  Operation FLINTLOCK was very big news in 1944, its overwhelming success has resulted in its obscurity today.  Other WWII island campaigns, which were not as successful or resulted in crippling American casualties, have now overshadowed events in the Marshalls. 

The Japanese presence in the Marshalls was of grave concern to American military officials, because the islands provided sheltered bases from which Japanese ships and planes could interdict the American supply lines to the Philippines.   Army and Navy war planners had labored since 1904 to devise a strategy that, in the event of a Japanese attack, would allow American forces to move across the Pacific Ocean to relieve the Army garrison in the Philippines.  Early war planners devised a scheme that called for the invasion of the Marshall Islands before advancing further across the Central Pacific.  A foothold in the Marshalls would provide American forces with a base of operations that would assure the recapture of the Philippines.   

These plans were renewed during World War II.  Admiral Chester Nimitz was not satisfied with attack plans against the outer islands of the Marshalls.  He insisted on a bolder move. He would go straight to the center of the Marshalls to the Japanese fleet headquarters at Kwajalein Atoll.  The invasion of Kwajalein Atoll would be the second time that an American force was thrown against a fortified island.  The first attempt, at Tarawa in the Gilbert Islands approximately 300 miles southeast of Kwajalein, had been a near disaster, with 990 Marines killed, 2,286 wounded.  Japanese casualties, 4,690 killed, left little doubt that they would fight to the last man.  Thus, many military planners questioned if an amphibious assault against a fortified position could ever work.  For this reason, the success or failure of the Marshalls invasion could affect future Allied strategy in the Pacific and in Europe.

The invasion of the Marshalls was a textbook operation.  Army, Navy, and Marine Corps planners carefully applied the lessons learned from Tarawa.  These included longer periods of aerial bombardment and naval gunfire support, the use of tracked amphibians, and the first use of frogmen (forerunners of Navy SEALS) to scout beaches and destroy underwater obstacles.  Maximum use of close-air support and the early introduction of armor and artillery were also used to great effect in the Kwajalein invasion.  The invasion fleet assembled off of Kwajalein in January,1944 was the largest ever assembled up till that time in World War II. The result was a nearly perfect operation that proved the utility of amphibious assault against fortified positions.  

The air campaign against the Marshall Islands began months before the invasion

Plans for the invasion of the Marshall Islands, code named Operation FLINTLOCK, were issued on December 20, 1943.  The 7th Infantry Division was designated the strike force for the invasion of Atoll's main island of Kwajalein Islet.  The 4th Marine Division were assigned the twin islets of Roi and Namur, forty five miles north of Kwajalein Islet.  Opposing the 7th Infantry Division on Kwajalein Islet were approximately 5,000 Japanese soldiers, airmen, sailors, and Korean laborers.  After several months of air strikes against many of the islands in the Marshalls, the five day operation began on January 31, 1944, when elements of the 7th Infantry Division began to seize small islands near Kwajalein to use as supply and fire support bases.

American artillery support was provided by 105mm and 155mm howitzers emplaced on Carlson (Enubuj) and Carlos (Ennylabegan) islands, which are north west of Kwajalein up the west reef.  Upwards of 29,000 rounds were fired against the landing beaches to soften up Japanese defenses. Starting at 0930 on February 1, 1944, the 7th Infantry Division landed over 1,200 troops in the first fifteen minutes of the invasion, and continued bringing men and equipment ashore during the entire operation.  The assault was conducted by the 184th Infantry regiment, which was responsible for moving up the lagoon side of the island, while the 32nd Infantry Regiment was responsible for the ocean side.  This end of the island, divided by the Japanese airstrip, provided an excellent sector line between the units. 

The 184th Infantry Regiment had been a California National Guard organization before the war and was added to the 7th Division during mobilization.  The 184th performed admirably during Operation Flintlock and subsequent 7th Division campaigns. 

Japanese defenses included elaborate concrete bunkers as well as coconut log machine gun nests.  Satchel charges and flame throwers were the only way to root out the defenders
By the end of the first day, American forces had grown to six infantry battalions, an engineer battalion, an armor battalion with sixty tanks and various support units.  During the day, most of the Japanese had fought from inside bunkers and pillboxes.  As night fell, the Japanese emerged from their bunkers and pillboxes during a chilling rainstorm and attacked American forward positions.  The first night for the Americans was long and dismal and filled with terror and confusion.

By the end of the second day (February 2) the full length of the airfield had been secured.  This was open ground, dotted with numerous concrete bunkers and rifle pits.  Each was taken in turn, but the assault remained on schedule.
A rifleman takes a K-Ration break while a BAR gunner cleans his weapon with dead Japanese nearby

American commanders expected to conclude the battle on February 3 against light Japanese resistance.  They were mistaken. The “Admiralty Area” just north of tip or the airfield, was the scene of some of the most intense fighting on Kwajalein.  Named by American intelligence officers because of the suspected location of the Japanese Naval headquarters, it was heavily developed with a large number of supply and administrative buildings, most of which had been reduced to rubble by bombing and shell fire.  This provided excellent cover for the Japanese defenders who had concentrated in this area.  They made the Americans pay for every inch of ground.  By day’s end, the 184th Infantry, still on the lagoon side of the island, and the 32nd Infantry on the ocean side, had not even reached that day’s first objective near present day 6th Street.  This day of fighting cost 310 Americans killed and wounded.  Over 1,100 Japanese died as well.  Many enemy soldiers committed suicide rather than surrender to the Americans.  Over two hundred dead Japanese were found in one large blockhouse.

American casualties began to mount on D+3

The 7th Infantry Division continued to meet stiff opposition on the last day of the battle. February 4th became the most difficult day as Japanese resistance strengthened while American soldiers pushed the Japanese to the end of the island.  A slight elevation in terrain near the end of the original islet (the modern Kwajalein is longer and wider than it was during WWII due to post War dredging and filling) marks the location of of a Japanese 5 inch dual-purpose gun mount.  The guns were captured late in the afternoon on February 4th by G Company, 2nd Battalion, 32nd Infantry Regiment.  Kwajalein was officially declared secure by General Charles Corlett, Commander of the 7th Infantry Division at 1610 hrs.  However, fighting continued to eradicate the last scattered Japanese resistance.  Captain Albert W. Pence of Company G, one of the last American casualties, was shot near this spot about 1900 hrs.   The last day of the battle proved to be the most costly, 317 Americans were killed and wounded on the 4th of February.

Tangled coconut trees offered cover for both friend and foe

Kwajalein Islet was only about 1.5 miles long and 1/2 mile wide at its widest point.  It took four days of fighting to secure it using every infantry battalion of the 184th and 32nd Regiments.  The division's reserve regiment, the 17th Infantry, was landed on Ebeye Islet a mile up the reef.  There it secured the Japanese sea plane base during two days of fighting.

Casualties for the 7th Division for all southern atoll islands were killed - 142, wounded - 845.  Japanese dead numbered 4938, with 206 captured (127 were Korean laborers).  US Marine losses on Roi-Namur Islet, forty five miles north of Kwajalein, included 190 Marines killed in action; and 547 wounded.  Japanese losses included 3,472 killed.  Fifty-one Japanese were captured along with 40 Korean laborers.

A battalion aid station stabilizes wounded GIs before they are evacuated from the island to ships offshore.  American KIAs were temporarily laid to rest on nearby Ennylabegan Island.  They were removed to cemeteries in the United States after the War.
The overwhelming number of Japanese dead after the battle resulted in a serious health hazard.  Some were gathered and placed in mass graves.  Others, such as these were buried in the fighting positions that they defended.  They remain still at Kwajalein in hundreds of un-marked and unknown graves. 
In a future blog entry, I'll describe the discovery and excavation of an inadvertently discovered mass burial at Kwajalein Island
The campaign for the Marshalls was best summed up by Marine Corps General Holland Smith who concluded that “very few recommendations can be made to improve upon the basic techniques previously recommended and utilized in the Marshalls.”  Lessons learned at Kwajalein were incorporated into every amphibious operation later in the war, including the landings in Normandy four months later.
Some on-line videos about Operation FLINTLOCK
1944 Newsreels, the Army on Kwajalein
1944 Newsreels, the Marines on Roi-Namur
Short History Channel video of the Kwajalein landing
Color video of the Marines at Roi-Namur


  1. This comment has been removed by a blog administrator.

  2. Warfare is a fascinating subject. Despite the dubious morality of using violence to achieve personal or political aims. It remains that conflict has been used to do just that throughout recorded history.

    Your article is very well done, a good read.

  3. I was there ! I am 92 in April , but I can recall the battle of Kwajalein quite well ! As an 18 year old kid from Oklahoma , who had joined the Navy , the experiences from the battle of Kwajalein were horrific ! There is too much to tell in my short time , but the most haunting memory to me as I write , is the truck loads of dead Japanese being dumped from trucks into dozed out deep ditches.

    1. Sir, thank you for your comment and your service. The Japanese are still there, and their graves are found on occasion during construction projects.