Following their bloody initiation in the opposed amphibious landing on Tarawa, American military planners devised Operation flintlock to bypass the heavily defended eastern atolls and strike directly at the administrative and communication complexes centrally located on Kwajalein. A secondary assault on Eniwetok (Operation catchpole) to the west would follow. flintlock incorporated lessons learned from the Tarawa experience. The Marshalls landings benefited from a sharp increase in the quality and quantity of naval gunfire support, large-scale air bombardments of the target prior to D day, and land-based artillery prepositioned on adjacent atolls to provide additional fire support. "Frogmen" of the newly created navy underwater demolition teams scouted the beaches for potential obstacles and marked the lanes for the landing craft. Requirements and procedures for landing assault troops were revamped to increase speed and efficiency in getting ashore, and the assaulting troops would have greatly increased firepower, including more automatic weapons, flamethrowers, and demolition charges.
An unprecedented two-day aerial and naval barrage preceded troop landings by the 4th Marine Division and the army's 7th Infantry Division on 1 February 1944. The Marines stormed Roi-Namur, two islands linked by a causeway on the atoll's northern tip, while the army took responsibility for seizing the main island of Kwajalein at the southern end. Although confusion plagued the Marines' initial ship-to-shore movement, the assault on Roi met with light resistance and secured the island's airfield in a single day.
The attack on Namur's supply facilities encountered heavier opposition, and only a portion of the island had been taken by nightfall. At least 120 American casualties occurred on Namur when engineers unknowingly detonated a bunker containing torpedo warheads. Just before daybreak on 2 February, the Marines repelled a counterattack by the remaining Japanese defenders and secured the island. The more orderly landings on Kwajalein met with substantial opposition, and it required four days of intense fighting to clear the island. Nearly the entire garrison of 8,675 Japanese soldiers on Roi-Namur and Kwajalein perished in these battles, with half of these casualties resulting from the preliminary bombardment. U.S. forces took only 265 prisoners, including 165 Korean laborers. U.S. losses were 372 dead and 1,582 wounded.
Operations flintlock and catchpole validated the American revised doctrine of amphibious warfare employing massive fire support and speed to achieve victory with minimum casualties. The success in the Marshall Islands actions also confirmed the wisdom of the Central Pacific "island-hopping" campaign, which called for bypassing and isolating Japanese strong points to move within striking distance of the Japanese home islands. Derek W. Frisby
Chapin, John C. Breaking the Outer Ring: Marine Landings in the Marshall Islands. Washington, DC: History and Museums Division, Headquarters, U.S. Marine Corps, 1994.; Lorelli, John A. To Foreign Shores: U.S. Amphibious Operations in World War II. Annapolis, MD: Naval Institute Press, 1995.; Millett, Allen R. Semper Fidelis: A History of the United States Marine Corps. Rev. ed. New York: Free Press, 1991.; Morison, Samuel E. History of United States Naval Operations in World War II. Vols. 2, 4, 5, 9, 10, and 11. Boston: Little, Brown, 1947–1952.; Moskin, J. Robert. The U.S. Marine Corps Story. Rev. ed. New York: McGraw-Hill, 1987.
Derek W. Frisby