Iwo Jima   19 Feb - 16 March 1945
An Airfield is Needed to Support the B-29's

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The Pacific War -- Hindsight lets us see that the main line of progress of the Pacific War from Pearl Harbor to Tokyo was : Gilberts : Tarawa and Makin, 21Nov43, to penetrate outer defenses of the Japanese conquests ; Marshalls : - Kwajalein 31Jan44 and Eniwetak 17Feb which was necessary steps to clear the way to a major goal of the Marianas : Siapan 15Jun-9July44, Guam 21July-10Aug , Tinian 24July-01Aug. As part of this operation, the Japanese carrier fleet was defeated at Philippine Sea 19Jun44, known as the "Mariana's Turkey Shoot." The Marianas placed Japan within range of a new bomber, the B-29 Superfortress. From the Marianas, the war making productive capabilities of Japan will be destroyed. Next came a requirement to support the Army's Landing on Leyte, Philippines, 20Oct44, and naval destruction of the Japanese battle fleet at Leyte Gulf, 23Oct-26Oct. MacArthur's efforts in land battle delay the next moves.  Iwo Jima, 19 Feb-16 March 1945, is needed to provide an airfield for fighter escort of bombers over Japan. And finally, Okinawa, 1Apr-21Jun, as a base for staging the actual invasion of Kyushu, Japan, home islands.

Iwo Jima contained two Japanese air fields that are used as a way point for air travel between the Carolinas and Japan, for attacks on the new airfields in the Marianas, and to intercept the very heavy bombers for the Marianas to Japan.
The American needs an airfield closer to Japan for fighter escorts to accompany bombers from the Mariana's airfields at Guam, Siapan and Tinian while over the targets in Japan. An equally valuable goal is a place for crippled bombers to land without crashing in the ocean. Iwo Jima is half-way between the Marianas airbases and Japan. The island is shy of 5 miles long, 2-1/2 miles wide at its widest at the north end and about 350 FEET above sea level. The island narrows to 700 yards at the south and ends with 580 foot Mt. Saribuchi.
Japanese Defenses
The Japanese had learned they can not defend a beach against USN bombardment. So how does one defend an island that was almost all beach? The Japanese build miles of underground tunnels connecting pill boxes and fighting trenches with underground garrisons. The underground headquarter bunker has walls with 10-feet of concrete. Gun emplacements have 4-foot walls and cannot be seen nor attacked from the air. They know the island cannot be saved, rather the goal is to kill as many attackers as possible so as to make the Americans willing to make a truce to the war rather than invade Japan. 26,000 Japanese troops are placed on Iwo Jima.
American Forces
Iwo Jima was one of several amphibious invasions conducted by the Marine Corp as their speciality. It was the largest, all-Marine operation. They arrive with 450 ships, 50,000 Marines, and 482 Amtrac vehicles, The amphibious landing boats with caterpillar tracs are able to take Marines through the surf and onto the beach -- the need for this was discovered at Tarawa. During the delay of the Philippines, the Japanese make the island into a fortress, even while it is bombed for 72 days by B-24's from the Marianas. The ships include 6 battleships, 4 cruisers, and 16 destroyers. The 14" guns and other naval guns bombard the island for three days. The guns stop and 8 battalions in ten waves hit the beach and the 9,000 landing troops ran into a loose, black volcanic sand, terraced so sharply that even tracked vehicles can not climb from the beach.
The Battle
There is no response to the bombardment, but beach reconnaissance earlier had been strongly attacked damaging 8 gun boats. However, there was no response during the landing, then the enemy come out of their 11 miles of tunnels to fire on the exposed Marines trying to climb the sand terraces. The first day objective of capturing an airfield only 500 yards inland is not obtained. Bulldozers have to make grades as steel mat applied for tanks to get on the island. Only tanks are effective in attacking the concrete pillboxes. By nightfall, 26,000 marines have landed with 5000 of them killed or wounded.
The battle had been expected to take a few days, but the Japanese strategy of attrition drag on for five weeks. The fortress of Mt. Suribachi is taken on 23 February with a famous photograph and statue. Virtually all of the 21,000 Japanese are killed with 216 captured and with three times that number of Marines killed or wounded.

Flag raised on Suribachi 23 February 1945

Most of these men were later killed or wounded in the fighting.

The U.S. Navy
The fleet carrier force (16 carriers) attacks Japan 16 Feb with naval aircraft for the first time destroying 500 aircraft before withdrawing in bad weather to be on hand for the invasion.
From Oct 44 (Battle of Leyte Gulf) the Japanese adopt suicide attack as a method of warfare. The invasion of Iwo Jima, within range of the home islands brings out both Kamikaze and bombers directly from Japan. Kamikazes sink the escort carrier Bismarck Sea (CVE-95) and damage Saratoga (CV-3), 21Feb45. The winter weather is bad and many ships are damaged or collide. Land based artillery and friendly fire also damage ships in waters around the small island. When Kamikazes arrive, the fleet carriers turned north again to attack air fields in southern Japan 25Feb and destroy 600 planes.
The Results
The island is declared secure 16 March. Marines suffer 25,581 casualties(1) of which 5,330 have been killed.
On March 3, 1945, a crippled B-29 out of fuel lands on Iwo Jima; it would have crashed in the ocean with its 10- man crew. Not ready for aircraft, the big bomber is refueled by a line of troops with helmets. As an emergency landing site, 2,250 B-29's take advantage of the refuge ; thus 22,500 airmen do not swim home. P-51 Mustang fighters are based on the island from 11 March ; B-29 attacks had begun on Japan from Siapan in late November'44. Iwo Jima will provide a protected right flank in the taking of Okinawa which will become a site for direct attack on Tokyo with light, medium, and B-24 bombers .
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Written on August 4, 2005
Updated December 26, 2019
URL: http://www.ww2pacific.com/iwojima.html