Operation Detachment: 1945 Battle of Iwo Jima (WW2 Pacific Military History Series Book 8) Read online

  Operation Detachment

  1945 Battle of Iwo Jima

  Daniel Wrinn

  Contents

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  The Pacific Offensive

  Operation Detachment

  Kuribayashi's Big Mistake

  D-Day on Iwo Jima

  Getting the Guns Ashore

  Prowling Wolves

  Suribachi-yama

  The Meatgrinder

  Northern Allied Drive

  Defiant to the End

  Legacy of Iwo Jima

  Iconic Flag Raising

  Allied Commanders

  General Kuribayashi

  Japanese Spigot Mortar

  Iwo’s Air Support

  Sherman Zippo Tanks

  Buck Rogers Men

  Logistical Support

  Also By Daniel Wrinn

  References

  About the Author

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  The Pacific Offensive

  March 4, 1945 was the second week of the Allied invasion of Iwo Jima. By now, the assault elements of the 3rd, 4th, and 5th Marine Divisions were drained, and their combat efficiency was seriously reduced.

  The thrilling sight of the American flag being raised by the 28th Marines on Mount Suribachi had happened ten days earlier—a lifetime ago on Sulfur Island. The Amphibious Corps landing forces had already suffered 13,000 casualties, including 3,000 dead. The front was a jagged serration across Iwo Jima’s fat northern half. Smack in the middle of the primary Japanese defenses. The Allied landing force had to advance uphill against a well-disciplined, entrenched, and rarely visible enemy.

  In the center of the island, the 3rd Marines spent the night turning back a small, but determined, enemy counterattack, which found a gap between the 21st and 9th Marines. Savage hand-to-hand combat had cost both sides heavy casualties. The counterattack ruined the division’s preparation for a morning advance, but both regiments made gains against stubborn enemy opposition.

  In the east, the 4th Marine Division secured Hill 382 at the cost of their combat efficiency plummeting below fifty percent. By nightfall, it would fall another five percent. The 24th Marines, supported by flame-throwing tanks, only advanced one hundred yards before stopping to detonate two tons of explosives against enemy cave positions. The 23rd and 25th Marines entered the most challenging terrain yet—a broken ground with visibility less than a few feet.

  On the western flank, the 5th Marine Division took Hill 362-B (Nishi Ridge) at the cost of over 500 casualties. They’d engaged a sizeable enemy force throughout the night. While the enemy attacks lacked coordination, exhausted Marines were barely able to hold them off. Most rifle companies were now at less than half strength. The division reported the net gain for the day as “practically nothing.”

  The battle took its toll on the enemy garrison as well. Japanese General Tadamichi Kuribayashi knew his 109th Division had inflicted heavy casualties on the assaulting Marines, but his losses were comparable. The Allied capture of the critical hills the day before denied him his prized artillery observation sites.

  Kuribayashi’s brilliant chief of artillery, Colonel Chosaku Kaido, had been killed. Kuribayashi moved his command post from the central highlands to a large cave on the northwestern coast. Imperial Headquarters in Tokyo had reached him by radio that afternoon, but the general was in no mood for heroic rhetoric. He replied: “Send air and naval support, and I will hold the island. Without them, I cannot hold.”

  That afternoon, the combatants witnessed a glimpse of Iwo Jima’s fate. Through the overcast skies, a giant silver bomber (the largest aircraft yet seen), the B-29 “Dinah Might,” came in for an emergency landing on the scruffy island airstrip. Allied troops held their breath as the bomber swooped in and landed with a thud. Clipping a field telephone pole with its wing and rumbling to a stop three feet from the end of the strip.

  Pilot Fred Malo and his ten-man crew didn’t stay long. Every enemy gunner within range wanted to bag this prize. Mechanics made hurried field repairs, and the sixty-five-ton Super Fortress scrambled through a hail of enemy fire, returning to its base on Tinian.

  The battle of Iwo Jima raged for another twenty-two days and claimed 11,000 more Allied casualties and the lives of nearly the entire Japanese garrison. A historic and colossal fight between two well-armed veteran forces. This was the bloodiest and biggest battle in the history of the Marine Corps. But after March 4, leaders on both sides had no doubts as to the ultimate outcome.

  Operation Detachment

  Iwo Jima was an amphibious landing where assault troops saw the value of the objective. They were finally within a thousand miles of the Japanese homeland—and contributing clearly in support of the Allied bombing campaign.

  This bombing campaign was a new wrinkle on an old theme. For forty years, Marines had been developing the skills to seize advanced naval bases in support of the fleet. In the Pacific war—especially at Tinian, Saipan, and now Iwo Jima—they secured advanced airbases to further the bombing of the Japanese home islands.

  Allied forces had waited for the arrival of the B-29s for years. These long-range bombers became operational too late for the European theater—but they’d been hitting Japan since November 1944 with disappointing results. The problem wasn’t the planes or pilots, but from a little spit of volcanic rock lying halfway across the path from Saipan to Tokyo—Iwo Jima.

  Radar on Iwo gave the enemy two hours’ advance notice of every B-29 strike. Japanese fighters on Iwo’s airfields would swarm and harass the unescorted Super Fortresses going in and especially returning to base. Enemy fighters picked off the B-29s crippled from antiaircraft fire. This caused the B-29s to fly higher and with a reduced payload.

  The Joint Chiefs decided Iwo Jima must be secured with an Allied airfield built there. This would stop Japanese bombing raids and early warning interceptions. The airfield would offer fighter escorts through the treacherous portions of the B-29’s missions and greater payloads at longer ranges. Iwo Jima in Allied hands would also provide emergency airfield support and landing for crippled B-29s returning from Tokyo and protect the Allied flank for the Okinawa invasion. Admiral Chester Nimitz was given three months to seize and develop Iwo Jima: codename Operation Detachment

  Iwo Jima translates to “Sulfur Island” in Japanese. An ugly, foul-smelling, barren chunk of volcanic rock and sand—not even ten square miles in size. According to a Japanese Army officer: “an island of sulfur, no sparrow, no swallow, no water.”

  Less poetic Marines described Iwo’s resemblance to a pork chop with a 556-foot volcano. Mount Suribachi dominated the southern end of the island and overlooked all potential landing beaches. Iwo rose unevenly over onto the Motoyama Plateau in the north before falling sharply off into the coast and steep cliffs and canyons. The northern terrain was a defender’s dream: an intricate, broken, cave-dotted jungle of stone. Ringed by volcanic steam and a twisted landscape that seemed like a barren moon wilderness. More than one surviving Marine compared the eerie silence to something out of Dante’s Inferno.

  Iwo Jima in 1945 had two redeeming characteristics: the military value of its airfields and the psychological status of the island as a historical Japane
se possession. The Allies were now within Japan’s Inner Defense Zone. According to a Japanese officer: “Iwo Jima is the doorkeeper to the Imperial capital.”

  Even with the slowest aircraft, Tokyo could be reached in three flight hours from the island. In the Iwo Jima battle, 20,000 Allied and Japanese troops would be killed during brutal fighting in the last winter months of 1945.

  No one suggested taking Iwo Jima would be easy. Admiral Nimitz assigned this mission to the same team who’d done so well in the earliest amphibious assaults in the Gilberts, Marshalls, and Marianas. Admiral Raymond Spruance would commend the 5th Fleet, Admiral Richmond Kelly Turner would commend the expeditionary forces, and Admiral Harry Hill would command the attack force.

  Operation Detachment required unrelenting military pressure on the enemy and an accelerated planning schedule. The Amphibious task force preparing to assault Iwo Jima was getting squeezed on both ends. Admiral Hill desperately needed amphibious ships, shore bombardment vessels, and landing craft that were currently in use by General Douglas MacArthur and his reconquest of the Philippines. Poor weather and stiff enemy resistance combined to delay the completion of that operation.

  The Joint Chiefs reluctantly postponed D-Day on Iwo from January 20 to February 19. The new schedule provided no relief for Allied planners. D-Day on Okinawa could be no later than April 1 because of the monsoon season. This tight timeframe held grim implications for the Marine landing force.

  General Harry Schmidt would command the V Amphibious Corps in the assault. Schmidt’s landing force consisted of three Marine divisions (3rd, 4th, and 5th). Schmidt would have the honor of commanding the largest US Marine force ever committed into a single battle—a force totaling over 80,000 troops.

  Over half of these troops were Marine veterans from earlier fighting in the Pacific. Realistic training had prepared new Marines for the hard fight to come. The Iwo Jima assault force was arguably the most proficient amphibious force the world had yet to see.

  Two senior Marines shared the limelight on Iwo Jima, and history has done them both an injustice. General Holland M. Smith, who then commanded the FMF (Fleet Marine Force), was tasked to participate in Operation Detachment as the Expeditionary Troops’ Commanding General. This was an unnecessary billet. Schmidt had the rank, experience, staff, and resources to execute core level responsibility without being second-guessed.

  General Smith was an amphibious pioneer and veteran of landings in the Gilberts, Marshalls, and the Marianas. According to him: “My sun had nearly set by then. I think they asked me along in case something happened to Harry Schmidt.” Smith would try to keep out of Schmidt’s way, but his decision to withhold the 3rd Marines (Expeditionary Troops Reserve) remains as controversial as it was in 1945.

  General Smith proved himself an asset to the Iwo Jima campaign. He was always a voice in the wilderness in the top-level planning stage. Smith predicted severe casualties unless more effective preliminary naval bombardment was provided. He diverted visiting dignitaries and the press away from Schmidt and always offered a realistic counterpoint to some of the rosier staff estimates. According to Smith: “It’s a tough proposition, that’s why we’re here.”

  General Schmidt’s few public statements left him saddled with predicting Iwo Jima would be conquered in ten days. According to post-war accounts, Schmidt resented Smith’s perceived role: “I was the commander of all troops on Iwo Jima at all times. Holland Smith never had an onshore command post, never issued a single order, and never spent a single night ashore. Isn’t it important from a historical standpoint that I commanded the greatest number of Marines ever to be engaged in a single action in the entire history of the Marine Corps?”

  General Smith did not disagree with those points. While Smith proved to be useful, Schmidt and his staff should be credited for planning and executing the difficult and bloody Iwo Jima campaign.

  The V Amphibious Corps’ conquest of Iwo Jima was even more remarkable due to tough enemy opposition on the island. General Kuribayashi was one of the most fearsome opponents of the war. Kuribayashi was a fifth-generation samurai handpicked by the emperor. The Japanese general combined combat experience with an innovative mind and an iron will.

  Although this would be his only struggle against US forces, he learned much about his opponents from earlier service in the US. Kuribayashi appraised with an unblinking eye the results of previous Japanese attempts to repel Allied invasions of Japanese-held garrisons.

  Aside from the heroic rhetoric, Kuribayashi saw little value in the defend-at-the-water’s-edge tactics and suicidal banzai attacks that branded Japan’s failures from Tarawa to Tinian. Kuribayashi was a realist. He did not expect much help from Japan’s depleted fleet and air forces. His best chance was to fortify Iwo’s forbidding terrain with an in-depth defense, similar to the defense on Peleliu. Kuribayashi would shun coastal defenses, anti-landing, and banzai tactics. Instead, he’d wage a battle of attrition: a war of patience, nerves, and time. A delay and bleed strategy. Would the Allied forces lose heart and abandon the campaign?

  A passive policy this late in the war was radical to senior Japanese Navy and Army leaders. It was counter to the deeply ingrained Bushido samurai code: a warrior code that viewed the defensive as only an unpleasant delay before the glorious offensive could resume—where the enemy would be destroyed by fire and sword. Imperial Headquarters was nervous. There was evidence of a top-level request for guidance in defending against Allied storm landings from Nazi Germany, whose experience trying to defend Normandy at the water’s edge had proven disastrous.

  Japanese command was unconvinced. Kuribayashi used his connection to the Emperor to avoid being relieved. But it was not a complete victory—the Navy insisted on building blockhouses and gun casements along the obvious landing beaches. Kuribayashi demanded assistance from the finest mining engineers and fortification specialists in the Empire.

  The island favored the defender. Iwo’s volcanic sand mixed with cement produced an exceptional concrete for installations. The soft rock was easy to dig. Over half of the Japanese garrison put their weapons aside and picked up picks and spades. When Allied bombers from the Seventh Air Force began a daily pummeling of the island in early December 1944, Kuribayashi just moved everything underground: weapons, command post, barracks, and aid stations. The engineering achievements he accomplished were extraordinary. Kuribayashi masked gun positions, created interlocking fields of fire, and miles of tunnels linking key defensive positions. Every cave had multiple outlets and ventilation tubes. One installation inside Mount Suribachi ran seven stories deep. Allied troops rarely encountered a live Japanese on the island until the bitter end.

  Allied intelligence, aided by documents captured in Saipan and by an almost daily flow of aerial surveillance, was puzzled by the Japanese garrison’s disappearing act. The photo interpreters, using stereoscopic lenses, listed 775 potential targets, but all were covered, hardened, and masked. Allied planners knew there was no fresh water available on the island. They saw the rainwater cisterns and knew what the average monthly rainfall would deliver. They determined the enemy garrison couldn’t survive under those conditions in numbers greater than 12,000 for long. But Kuribayashi’s force was twice that size. His troops had existed on half rations of water for months before the battle even began.

  Unlike the earlier amphibious assaults on Guadalcanal and Tarawa, Allies would not have a strategic surprise on Iwo. Japanese headquarters believed Iwo would be invaded after the loss of the Marianas. Six months before the battle, Kuribayashi wrote to his wife: “the Americans will most definitely invade Iwo Jima—do not look for my return.”

  Kuribayashi ruthlessly worked his men to complete the defensive and training preparations by February 11, 1945. The general met his objective. Kuribayashi had a mixed force of recruits and veterans, soldiers and sailors. His artillerymen and mortar crews were the best in the Empire. Still, he trained and disciplined them all. Each fighting position had the commander’s “C
ourageous Battle Vows” prominently posted above the firing apertures. Troops were cautioned to maintain their position and to take ten Marine lives for each Japanese death.

  General Schmidt issued the operational plan on December 23, 1944. This plan wasn’t fancy. Mount Suribachi towered over the potential landing beaches, but the 3,000 yards of black sand along the southeastern coast were more sheltered from the prevailing winds. It was here the V Amphibious Corps would land on D-Day. The 4th Marine Division on the right, the 5th on the left and the 3rd in reserve. The primary objectives were the lower airfield and Suribachi. Then, the assault force would swing into line and attack north shoulder to shoulder.

  Anticipating a significant enemy counterattack on the first night, General Holland Smith said: “We welcome their counterattack. That’s generally when we break their back.”

  Kuribayashi's Big Mistake

  The physical separation of the three Marine divisions from Hawaii to Guam had no apparent adverse effect on their training. The proficiency of small units in combined arms assaults on fortified positions and amphibious landing were where it counted most. Each division was well prepared for the invasion.

  The 3rd Marines had just completed their part in the liberation of Guam. Their field training often included active combat patrols to root out and destroy stubborn enemy survivors.

  On Maui, the 4th Marine Division prepared for their fourth assault landing in thirteen months with quiet confidence. According to Major Fred Karch: “We had a continuity of veterans that was unbeatable.”