Marines in World War II Commemorative Series
Assault Preparations
The Drive North
The Bitter End
Iwo Jima's Costs, Gains, and Legacies
The Japanese Commander
The Assault Commanders at Iwo Jima
Above and Beyond the Call of Duty
Special Subjects
Rosenthal's Photograph of Iwo Jima Flag-Raising
The Japanese 320mm Spigot Mortar
Marine Corps Air Support During Iwo Jima
The Marine's Zippo Tanks
Iwo's Fire Brigades: The Rocket Detachments
Amphibious Logistical Support at Iwo Jima
Assault Divisions' Command Structures

CLOSING IN: Marines in the Seizure of Iwo Jima
by Colonel Joseph H. Alexander
U.S. Marine Corps (Ret)

The Drive North

The landing force still had much to learn about its opponent. Senior intelligence officers did not realize until 27 February, the ninth day of the battle, that General Kuribayashi was in fact on Iwo Jima, or that his fighters actually numbered half again the original estimate of 13,000.

For Kuribayashi, the unexpectedly early loss of the Suribachi garrison represented a setback, yet he occupied a position of great strength. He still had the equivalent of eight infantry battalions, a tank regiment, two artillery and three heavy mortar battalions, plus the 5,000 gunners and naval infantry under his counterpart, Rear Admiral Toshinosuke Ichimaru. Unlike other besieged garrisons in the Central Pacific, the two Japanese services on Iwo Jima functioned well together.

Kuribayashi was particularly pleased with the quality of his artillery and engineering troops. Colonel Chosaku Kaido served as Chief of Artillery from his seemingly impregnable concrete blockhouse on a promontory on the east central sector of the Motoyama Plateau, a lethal landmark the Marines soon dubbed "Turkey Knob," Major General Sadasue Senda, a former artillery officer with combat experience in China and Manchuria, commanded the 2d Independent Mixed Brigade, whose main units would soon be locked into a 25-day death struggle with the 4th Marine Division. Kuribayashi knew that the 204th Naval Construction Battalion had built some of the most daunting defensive systems on the island in that sector. One cave had a tunnel 800 feet long with 14 separate exits; it was one of hundreds designed to be defended in depth.

The Japanese defenders waiting for the advance of the V Amphibious Corps were well armed and confident. Occasionally Kuribayashi authorized company-sized spoiling attacks to recapture lost terrain or disrupt enemy assault preparations. These were not suicidal or sacrificial. Most were preceded by stinging artillery and mortar fires and aimed at limited objectives. Kuribayashi's iron will kept his troops from large-scale, wasteful Banzai attacks until the last days. One exception occurred the night of 8 March when General Senda grew so frustrated at the tightening noose being applied by the 4th Marine Division that he led 800 of his surviving troops in a ferocious counterattack. Finally given a multitude of open targets, the Marines cut them down in a lingering melee.

plume of smoke
Marine half-track scores a hit on a Japanese strongpoint with its 75mm gun. Marine Corps Historical Collection

For the first week of the drive north, the Japanese on Iwo Jima actually had the attacking Marines outgunned. Japanese 150mm howitzers and 120mm mortars were superior to most of the weapons of the landing force. The Marines found the enemy direct fire weapons to be equally deadly, especially the dual-purpose antiaircraft guns and the 47mm tank guns, buried and camouflaged up to their turrets. "The Japs could snipe with those big guns," said retired Lieutenant General Donn J. Robertson. The defenders also had the advantage of knowing the ground.

Not surprisingly, most casualties in the first three weeks of the battle resulted from high explosives: mortars, artillery, mines, grenades, and the hellacious rocket bombs. Time correspondent Robert Sherrod reported that the dead at Iwo Jima, both Japanese and American, had one thing in common: "They all died with the greatest possible violence. Nowhere in the Pacific War had I seen such badly mangled bodies. Many were cut squarely in half."

Close combat was rough enough; on Iwo Jima the stress seemed end less because for a long time the Marines had no secure "rear area" in which to give shot-up troop units a respite. Kuribayashi's gunners throughout the Motoyama Plateau could still bracket the beaches and airfields. The enormous spigot mortar shells and rocket bombs still came tumbling out of the sky. Japanese infiltrators were drawn to "softer targets" in the rear. Anti-personnel mines and booby traps, encountered here on a large scale for the first time in the Pacific, seemed everywhere. Exhausted troop units would stumble out of the front lines seeking nothing more than a helmet-full of water in which to bathe and a deep hole in which to sleep. Too often the men had to spend their rare rest periods repairing weapons, humping ammo, dodging major-caliber incoming, or having to repel yet another nocturnal Japanese probe.

The drive north by the 3d Battalion, 28th Marines, enters rugged terrain. Under heavy Japanese fire, this attack netted only 200 yards despite supporting fires. Department of Defense Photo (USMC) 111988

General Schmidt planned to attack the Japanese positions in the north with three divisions abreast, the 5th on the left, the 3d (less the 3d Marines) in the center, and the 4th on the right, along the east coast. The drive north officially began on D+5, the day after the capture of Suribachi. Prep fires along the high ground immediately north of the second airfield extended for a full hour. Then three regimental combat teams moved out abreast, the 26th Marines on the left, the 24th Marines on the right, and the 21st Marines again in the middle. For this attack, General Schmidt consolidated the Sherman tanks of all three divisions into one armored task force commanded by Lieutenant Colonel William R. "Rip" Collins. It would be the largest concentration of Marine tanks in the war, virtually an armored regiment. The attack plan seemed solid.

The Marines soon realized they were now trying to force passage through Kuribayashi's main defensive belt. The well-coordinated attack degenerated into desperate, small-unit actions all along the front. The 26th Marines on the left, aided by the tanks, gained the most yardage, but it was all relative. The airfield runways proved to be lethal killing zones. Marine tanks were bedeviled by mines and high-velocity direct fire weapons all along the front. On the right flank, Lieutenant Colonel Alexander A. Vandegrift, Jr., son of the Commandant, became a casualty. Major Doyle A. Stout took command of the 3d Battalion, 24th Marines.

The Japanese 320mm Spigot Mortar

Marine with mortar shell
Department of Defense Photo

One of the unique Japanese weapons that Marines encountered on Iwo Jima was the 320mm spigot mortar. These enormous defensive weapons were emplaced and operated by the Japanese Army's 20th Independent Mortar Battalion.

The mortar tube, which had a small cavity at the muzzle, rested on a steel baseplate which, in turn, was supported by a wooden platform. Unlike a conventional mortar, the five-foot long projectile was placed over the tube instead of being dropped down the barrel. The mortar shell had a diameter of nearly 13 inches, while the mortar tube was little more than 10 inches wide. The weapon could hurl a 675-pound shell a maximum of 1,440 yards. The range was adjusted by varying the powder charge, while changes in deflection were accomplished by brute force: shoving and pushing the base platform.

Although the tubes only held out for five or six rounds, enough shells were lobbed onto Marine positions to make a lasting impression on those who suffered through that campaign. According to a platoon leader who served with the 28th Marines, the spigot mortar (referred to as "the screaming Jesus" in his unit) was always afforded a healthy respect and, along with the eight-inch Japanese naval rocket, remains one of his most vivid memories of Iwo Jima. General Robert E. Cushman, Jr., who commanded the 2d battalion, 9th Marines, at Iwo Jima and went on to become the 25th Commandant of the Marine Corps, recalled that the tumbling projectile's inaccuracy made it that much more terrifying. "You could see it coming," he said, "but you never knew where the hell it was going to come down."

Kenneth L. Smith-Christmas

During the fighting on D+5, General Schmidt took leave of Admiral Hill and moved his command post ashore from the amphibious force flagship Auburn (AGC 10). Colonel Howard N. Kenyon led his 9th Marines ashore and into a staging area. With that, General Erskine moved the command post of the 3d Marine Division ashore; the 21st Marines reverted to its parent command. Erskine's artillery regiment, the 12th Marines under Lieutenant Colonel Raymond F. Crist, Jr., continued to land for the next several days. Schmidt now had eight infantry regiments committed. Holland Smith still retained the 3d Marines in Expeditionary Troops reserve. Schmidt made the first of several requests to Smith for release of this seasoned outfit. The V Amphibious Corps had already suffered 6,845 casualties.

expended ammunition shells
Expended shells and open ammunition boxes testify to the heavy supporting fire this water-cooled, .30-caliber Browning machine gun poured on the enemy as Marines advanced in the furious and difficult battle for the heights of Suribachi. Department of Defense Photo (USMC) 110604

The next day, D+6, 25 February, provided little relief in terms of Japanese resistance. Small groups of Marines, accompanied by tanks, somehow made it across the runway, each man harboring the inescapable feeling he was alone in the middle of a gigantic bowling alley. Sometimes holding newly gained positions across the runway proved more deadly than the process of getting there. Resupply became nearly impossible. Tanks were invaluable; many were lost.

Schmidt this day managed to get on shore the rest of his corps artillery, two battalions of 155mm howitzers under Colonel John S. Letcher. Well directed fire from these heavier field pieces eased some of the pressure. So did call fire from the cruisers and destroyers assigned to each maneuver unit. But the Marines expressed disappointment in their air support. The 3d Marine Division complained that the Navy's assignment of eight fighters and eight bombers on station was "entirely inadequate." By noon on this date General Cates sent a message to Schmidt requesting that "the Strategic Air Force in the Marianas replace Navy air support immediately." Colonel Vernon E. Megee, now ashore as Air Commander Iwo Jima and taking some of the heat from frustrated division commanders, blamed "those little spit-kit Navy fighters up there, trying to help, never enough, never where they should be."

In fairness, it is doubtful whether any service could have provided effective air support during the opening days of the drive north. The Air Liaison Parties with each regiment played hell trying to identify and mark targets, the Japanese maintained masterful camouflage, front-line units were often "eyeball-to-eyeball" with the enemy, and the air support request net was overloaded. The Navy squadrons rising from the decks of escort carriers improved thereafter, to the extent that their conflicting missions would permit. Subsequent strikes featured heavier bombs (up to five hundred pounds) and improved response time. A week later General Cates rated his air support "entirely satisfactory." The battle of Iwo Jima, however, would continue to frustrate all providers of supporting arms; the Japanese almost never assembled legitimate targets in the open.

"The Japs weren't on Iwo Jima," said Captain Fields of the 26th Marines, "they were in Iwo Jima."

Richard Wheeler, who survived service with the 28th Marines and later wrote two engrossing books about the battle, pointed out this phenomenon:

This was surely one of the strangest battlefields in history, with one side fighting wholly above the ground and the other operating almost wholly within it. Throughout the battle, American aerial observers marveled at the fact that one side of the field held thousands of figures, either milling around or in foxholes, while the other side seemed deserted. The strangest thing of all was that the two contestants sometimes made troop movements simultaneously in the same territory, one maneuvering on the surface and the other using tunnels beneath.

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Commemorative Series produced by the Marine Corps History and Museums Division