Operation Detachment (Iwo Jima)

Operation Detachment (Iwo Jima)
Name	Operation Detachment
Partof	Pacific War and Battle of Iwo Jima
Date	19 February – 26 March 1945
Place	Iwo Jima
Result	Allied victory
Combatant1	United States (United States Marine Corps and United States Navy)
Combatant2	Empire of Japan (Imperial Japanese Army and Imperial Japanese Navy)
Commander1	Gen. Thomas Holcomb; Gen. Holland M. "Howlin' Mad" Smith; Holland M. Smith; Harry Schmidt; H. M. Smith; Adm. Chester W. Nimitz; Adm. Raymond A. Spruance
Commander2	Tadamichi Kuribayashi
Strength1	~70,000 Marines and sailors with air support from United States Army Air Forces
Strength2	~21,000 soldiers and naval troops

Operation Detachment (Iwo Jima) was the United States United States Marine Corps and United States Navy amphibious assault to seize Iwo Jima from the Empire of Japan during the Pacific War (World War II), executed between 19 February and 26 March 1945. The operation aimed to secure airfields for United States Army Air Forces escort and emergency landings for Boeing B-29 Superfortress bombers en route to Tokyo. The battle became noted for its intense fortifications conceived by Tadamichi Kuribayashi and the iconic photograph of the Raising the Flag on Iwo Jima.

Background

In late 1944 and early 1945 the United States Pacific Fleet and Joint Chiefs of Staff pursued a campaign of island-hopping across the Central Pacific Campaign, following Battle of Saipan and Battle of Leyte Gulf, to bring airfields closer to the Japanese home islands. The capture of Iwo Jima was linked to operations against Okinawa, the planned Operation Downfall, and strategic bombing of Japan. Japanese strategic planners under the Imperial General Headquarters sought to deny U.S. airfields and to maximize attrition, guided by lessons from Battle of Guadalcanal and Battle of Saipan.

Planning and preparations

Planning for the assault involved the United States Fifth Fleet, United States Third Fleet, United States Seventh Fleet, and Southwest Pacific Area commanders coordinating naval gunfire, carrier aviation, and amphibious forces. Admiral Chester W. Nimitz and Admiral Raymond A. Spruance authorized pre-invasion bombardments using Iowa-class battleship and South Dakota-class battleship fire and carrier strikes from USS Enterprise (CV-6) and USS Essex (CV-9), while United States Marines trained in Amphibious Corps, Pacific Fleet doctrines at Camp Pendleton and Camp Lejeune. Japanese commander Tadamichi Kuribayashi rejected beach defenses in favor of an elaborate system of bunkers, tunnels, and inland strongpoints centered around airfields later designated as Motoyama. Intelligence from Naval Intelligence and Joint Intelligence attempted to assess fortifications but underestimated tunnel networks and logistical stockpiles.

Order of battle

The American invasion force comprised elements of V Amphibious Corps including 3rd Marine Division, 4th Marine Division, and the 5th Marine Division, supported by artillery regiments, Seabees, USS Indianapolis (CA-35)-class cruisers, and carrier air groups from Task Force 58. Ground logistics were coordinated with Army Service Command elements and Naval Shore Establishments. Defenders on Iwo Jima included the 109th Division, detachments of Imperial Japanese Navy Land Forces, engineers organized into defense units, and garrison commanders under General Kuribayashi.

Invasion and main operations

On 19 February 1945 amphibious landings began at Red Beach and Yellow Beach under heavy naval bombardment and carrier strikes, with naval gunfire from Iowa-class battleship USS Missouri (BB-63) and California-class battleship USS South Dakota (BB-57). Marines of the 4th Marine Division and 5th Marine Division encountered fierce resistance from prepared positions, counterattacks coordinated by Tadamichi Kuribayashi, and obstructed beach exits reminiscent of Okinawa landings difficulties. Over subsequent days units such as 2nd Battalion, 28th Marines advanced on Mount Suribachi, culminating on 23 February in the Raising the Flag on Iwo Jima by members of Flag raisers and Sergeant Mike Strank's platoon photographed by Joe Rosenthal. Inland fighting evolved into attritional assaults against fortified bunkers and tunnel complexes, with engineering units and flamethrower teams supported by M4 Sherman tanks and LVT (Landing Vehicle Tracked) variants, while carrier-based Grumman F6F Hellcat and Vought F4U Corsair aircraft provided close air support from Task Force 58.

Casualties and losses

Casualty figures included approximately 6,800 killed and 19,000 wounded among United States Marine Corps and United States Navy personnel, with additional non-battle losses among United States Army Air Forces crews who crashed on-approach. Japanese casualties were catastrophic, with most of the approximately 21,000 defenders killed and about 216 taken prisoner; these figures reflect the Imperial Japanese Army policy against surrender influenced by Banzai charge doctrines and orders from the Imperial General Headquarters. Materiel losses included damaged and destroyed naval vessels from shore battery hits, numerous LVT and Sherman losses, and extensive destruction of airfield infrastructure on Iwo Jima.

Aftermath and strategic impact

The capture of Iwo Jima provided United States Army Air Forces with emergency landing fields for Boeing B-29 Superfortress bombers, reduced losses among downed bomber crews reaching Chichi Jima or Saipan and increased mission flexibility for Marianas-based bombing campaign flights to Tokyo. The psychological and political effects resonated across United States public opinion and were memorialized with the Marine Corps War Memorial in Arlington, Virginia, inspired by the Raising the Flag on Iwo Jima photograph by Joe Rosenthal. For the Empire of Japan, the battle depleted veteran formations and influenced defensive adaptations for the forthcoming Battle of Okinawa and the anticipated Operation Downfall. Operational lessons on amphibious assault, combined arms coordination, and fortification neutralization informed postwar doctrines in the United States Marine Corps and United States Navy.

Category:Pacific War battles Category:United States Marine Corps operations