Military Intelligence Service
Battle of Okinawa
by Ted Tsukiyama
The Battle of Okinawa has been called the largest sea-land-air battle in history. It is also the last battle of the Pacific War.
Three months of desperate combat leave Okinawa a "vast field of mud, lead, decay, and maggots."
More than 100,000 Okinawan civilians perish, with over 72,000 American and 100,000 Japanese casualties.
[The following is excerpted from Ted Tsukiyama's The Battle of Okinawa manuscript.]
Pre-Invasion of Okinawa
The April 1st invasion was preceded by 7 days of "softening up" artillery fire of 13,000 rounds by U.S. Navy guns and 3,095 sorties by carrier planes from Task Force 58 at the proposed landing sites at Hagushi and Chatan beaches.
Then on the morning of April 1st, navy ships rained a prelanding bombardment of 44,825 shells, 33,000 rockets and 22,500 mortar shells plus napalm attacks by carrier planes on the invasion beaches. This was the incendiary prelude to the Battle of Okinawa which Masahide Ota was to aptly and vividly describe in his book as "the typhoon of steel and bombs!"
Invasion of Okinawa
In the early pre-dawn twilight of April 1, 1945, Sgt. Takejiro Higa of the 314th Language Detachment of the U.S. 96th Infantry Division peered out at the familiar Okinawan coastline from the deck of an invasion ship with a sinking heart. Conflicting emotions churned within him: "I have a duty and responsibility as an American soldier. But why must I invade the home of my ancestors?" He stood on deck facing the approaching island with tears streaming down his cheeks.
As the U.S. forces prepared to make land, little did Higa realize that he was to witness and participate in "Operation Iceberg," the bloodiest and most bitterly fought battle of the Pacific War where almost 240,000 American, Japanese and Okinawan lives were lost and the island of Okinawa left devastated and ravished.
The American attacking force consisted of 183,000 troops of the U.S. Tenth Army and Marine Divisions commanded by General Simon Bolivar Buckner, supported by Navy and Air Force fire and bombardment. Okinawa was defended by 77,000 troops of the Japanese 32nd Army commanded by Gen. Mitsuru Ushijima, assisted by Lt.Gen Isamu Cho and Col. Hiromichi Yahara, and augmented by conscripted 20,000 "Boeitai" (Okinawa Home Guard) as labor and service troops and 750 middle school boys organized into the "Tekketsu Kinnotai" (Blood and Iron Corps).
For "Operation Iceberg," Pacific Commander Admiral Nimitz had assembled and launched the greatest amphibious invasion force of the Pacific War, as the horizon of the offshore sea was almost obliterated with hundreds and hundreds of ships moving toward the invasion beaches.
As the pre-H Hour bombardment lifted, an 8-mile long line of amphibious assault and landing craft moved shoreward onto the Hagushi and Chatan beachheads landing 60,000 assault troops, surprisingly without any enemy fire or resistance.
20 kilometers to the south from the top of Shuri Castle, General Ushijima and his staff calmly peered through binoculars, witnessing the devastating bombardment followed by thousands of American troops landing on the beaches unmolested, laughing and bemused that the enemy had wasted all that valuable ammunition on undefended ground. But this was all in accordance with the Japanese strategy to conserve its troop strength concentrated in the southern end of Okinawa, by allowing an initial enemy landing but to strenuously defend against the invading Americans at the strongly fortified Naha-Shuri-Yonabaru defense line.
Col. Yahara summarized the overall Japanese military strategy and philosophy of the Japanese defenders on Okinawa as the jikyusen, war of attrition, thusly:
"Japan was frantically preparing for a final decisive battle on the home islands, leaving Okinawa to face a totally hopeless situation. From the beginning I had insisted that our proper strategy was to hold the enemy as long as possible, drain off his troops and supplies, and thus contribute our utmost to the final decisive battle for Japan proper." (Yahara, The Battle for Okinawa, p. 49)
Translated into real terms, this dark outlook was to render the entire Japanese forces, the total land and resources of Okinawa and all of its residents, to become totally expendable in Japan's defense of Okinawa.
The scales of military strategy were balanced out when soon after the landing, a captured Japanese document was referred to XXIV Corps Headquarters G-2 Nisei personnel, Dan Nakatsu, Kenichi Ota and Herbert Nishita for translation. This was a battle plan prepared by Japan's military genius, Col. Yahara, Deputy Chief of Staff, for General Ushijima, which not only predicted the exact date of the April 1 invasion but the American objectives of Kadena and Yontan (Yomitan) air bases, the expected American battle routes, and the Japanese defense positions, strategy and tactics. Early in the battle, U.S. commanders thus learned how well organized and heavily defended Okinawa would be in the bloody days to come.
The American assault units landing on the beachheads moved inland and quickly captured the Kadena and Yomitan airfields. Lt. Lloyd M. Pierson of the 38th Japanese Order of Battle Team recalls going ashore on the second assault wave, landing with Takejiro Higa and advancing inland together through the rural Okinawan countryside.
Upon making the unopposed landing on D-Day April 1st, American Army and Marine forces quickly advanced inland cutting through Koza, Shimabuku and Momobaru to reach Nakagusuku Bay on the Pacific Ocean side in two days and effectively cutting the island and its Japanese defenders in half.
Conquest of Northern Okinawa
Commencing April 4, the 6th Marine Division launched its drive from Nakodomari-Ishikawa line up the narrow Ishikawa Isthmus against light resistance to reach the Nago-Taira line by April 7th. Three thousand Japanese of the 44th Infantry led by Col. Udo were entrenched in a defensive stronghold atop Yae-Dake, the highest point of the Motobu Peninsula.
On April 14, the U.S. 4th and 29th Marine Regiments launched an all-out assault on Yae-Dake with artillery, air and naval fire support, and there ensued one of the bitterest battles of the Okinawan campaign. Finally on April 18, Yae-Dake was captured after the Japanese defenders suffered 2,500 killed and 46 captured, and at a cost of 236 Americans killed and 1,061 wounded.
Capture of Ie Shima
The island of Ie Shima (or "Ie Jima") lying 4 miles west of Motobu peninsula held one of the largest airfields in the Asia-Pacific region and was vitally needed to provide air support to the assault on Okinawa.
On April 16, aerial and naval artillery, rocket and mortar bombardment saturated Ie Shima to soften up the beachhead landing of the U.S. 77th Division. Ie Shima was defended by an estimated 7,000 soldiers of the 44th Independent Mixed Brigade commanded by Major Tadashi Ikawa (the "Ikawa Unit") entrenched in heavily and intricately fortified pillboxes, gun emplacements, tunnels and caves centered around Ie town, Bloody Ridge and Iegusugu hill ("The Pinnacle").
The advance and encirclement of the Ie defenses by the 305th, 306th and 307th Regiments was stubbornly resisted by the Japanese defenders for six days. On April 17, the renowned war correspondent Ernie Pyle was killed by a hidden machine gun on the outskirts of Ie town.
On April 21 Ie Shima was declared secure after 4,706 Japanese were killed and 149 captured with 1,500 Okinawan civilians dead while at a cost of 172 Americans killed, 902 wounded and 46 missing. Maj. Gen Andrew Bruce declared "the last three days of fighting were the bitterest I have ever witnessed."
Japanese Air and Sea Counterattacks
On April 6, 400 Japanese attack planes flew out from Kyushu to launch "kamikaze" attacks on the American invasion forces and hundreds of American warships, troopships, supply vessels and landing craft offshore from the beachheads, inflicting heavy damage. They were met by U.S. Navy taskforce carrier planes and withering anti-aircraft fire, resulting in the loss of over 300 Japanese planes.
That night remnants of the Japanese fleet including the mighty battleship "Yamato" steamed out of Kyushu to meet the American flotilla off Okinawa, but on April 7th planes from Task Force 58 intercepted the Japanese armada in the East China Sea, directing bombing and torpedo attacks against the enemy fleet, sinking the pride of the Japanese Navy the "Yamato," cruiser "Yahagi" and three destroyers and destroying the last remnants of the Japanese Navy for good.
Japanese suicide attacks against American troops and ships continued through the month of April, inflicting heavy damage and casualties but losing up to 1,100 Japanese planes.
Southern Okinawa Campaign
After U.S. forces cut the island of Okinawa in two, the main invasion forces, principally the XXIV Corps, were ordered to turn and drive southward toward Shuri as the main objective, while the Japanese enemy ordered their troops to hold ground at any cost. The Japanese had long prepared "the Shuri Line" as its main line of defense and were ready:
"The main zone of defense was planned as a series of concentric positions adapted to the contours of the area. Caves, emplacements, blockhouses, and pillboxes were built into the hills and escarpments, connected by elaborate underground tunnels and skillfully camouflaged; many of the burial tombs were fortified. The Japanese took full advantage of the terrain to organize defensive areas and strong points that were mutually supporting, and they fortified the reverse as well as the forward slopes of hills. Artillery and mortars were emplaced in the caves and thoroughly integrated into the general scheme of defensive fires." (Okinawa: The Last Battle, p. 95)
For the first two days the XXIV Corps advanced easily southward through light enemy resistance until April 5 when it encountered a hail of effective fire from entrenched Japanese positions along the Machinato-Nishibaru-Ouki line and were forced to withdraw. On April 6-9, the 7th and 96th Infantry Divisions took Cactus Ridge (Mashiki), Red Hill (Minami-Uebaru), and Triangulation Hill and Tomb Hill (Ouki) after fierce resistance by Japanese defenders, until encountering the defensive stronghold of Kakazu Ridge.
On April 9 the 96th Division opened the first of several attacks against the Kakazu line, all of which were repulsed by savage Japanese defenses during the next four days, particularly from artillery and mortar fire fr9m well concealed firing positions. The fierce Japanese defense encountered was described by Navy Intelligence Officer Frank B. Gibney, as follows:
"For the next two weeks the war settled down to the most bitter, ruthless kind of hand-to-hand fighting, as GIs and marines desperately tried to claw their way up heavily defended rocky escarpments. The advancing troops were exposed not merely to constant mortar, machine gun, and rifle fire, but they took a pounding from General Wada's artillery. It was the worst fighting of the Pacific war, its sustained intensity surpassing even the brutal combat of Tarawa, Peleliu, and Iwo Jima." (Yahara, The Battle for Okinawa, p.33-34)
About this time a major breakthrough occurred when a map was found on a dead Japanese artillery officer in a forward observers' position which was immediately sent to XXIV Corps Headquarters G-2. There, Nisei MIS linguists of the 306th and 307th HQ Intelligence Detachments led by Dan Nakatsu and George Takabayashi translated the map to reveal the positions, ranges and bearings of all Japanese artillery and mortar emplacements on Okinawa, a tremendous and priceless find!
The Japanese map was overlayed on to U.S. artillery maps and distributed to all American attacking forces. The theretofore hidden Japanese gun emplacements were no longer a mystery, and were subsequently neutralized and destroyed by pinpointed American artillery, mortar and napalm fire.
Then on April 12 Gen. Ushijima ordered an all-out counterattack to recover the Yomitan and Kadena airfields, at the urgings of diehard elements of the 32nd Army staff led by Lt. Gen. Cho but violently opposed by Operations Officer Col. Yahara.
Preceded by intense artillery bombardment, Japanese troops infiltrated the American defenses along the Machinato-Kakazu-Ouki line on the night of April 12 and advanced northward as far as Ginowan. The Japanese launched attacks on April 13 and 14, each to be beaten down with almost total Japanese losses and resulting in total failure.
Attacking the Outer Shuri Defenses
On April 19, the U.S. 7th, 27th and 96th Divisions threw their offensive weight against the Japanese entrenched along the Machinato-Ouki line after a dawn artillery bombardment of 19,000 shells. But after bitter fighting the U.S. attackers were stopped cold at Urasoe-Mura, Tombstone Nishibaru-Kakazu and Skyline (Ouki) defensive strongholds suffering 720 casualties. The drive toward Shuri was stopped.
On April 20, the 165th Infantry of the 27th Division threw itself against the Gusukuma defenses but was repulsed by well dug-in enemy defense and fire around the strong point of "Item Pocket," holding off the American attackers for 7 days.
The 27th Division went on to overcome the twin Pinnacle defenses near Nakama by April 23 after suffering heavy casualties. The Outer Shuri Line stretching from Ouki, Tanabaru, Nishibaru, Kakazu and Urasoe-Mura Escarpment was savagely defended by the enemy entrenched in caves, tunnels and tombs prepared with criss-crossed fields of artillery, mortar and automatic fire over all approaches.
Inflicting great losses and casualties, the Japanese yielded no ground and fought to death. But after Americans had won bitterly earned break-throughs at key points along the First Shuri Line, Japanese defenders then withdrew from the Outer Shuri Line during the night of April 24 under cover of fog and heavy artillery fire to take up the defense of Shuri and Naha.
Assaulting the Main Shuri Defense Line
Japanese defenders had fallen back to a defense line stretching from Jichaku through Nakama, Maeda, Kochi to Conical Hill (Yonabaru). On April 26, Gen. Buckner ordered the 1st and 6th Marine Divisions and 77th Infantry Division to join the attacking American forces against the Shuri Line and there followed over 4 weeks of the severest fighting of the Pacific War until Shuri was finally taken.
The May 4 Counter-offensive
During the last days of April, American infantrymen led by flame-throwing tanks met with fierce resistance from the well entrenched Japanese defenders along the Asa River, Maeda Escarpment and Kochi ridges and were initially repulsed suffering heavy casualties.
Then from May 4 - 6, again at Gen. Cho's urging over Col. Yahara's objections, Gen. Ushijima ordered the Japanese 24th Division to lead a land-sea-kamikaze air counter-offensive to recapture all ground lost to the Americans. Japanese troops on landing barges attempted to encircle and land behind American lines but were soon annihilated. Kamikazes attacked U.S. Naval shipping.
On May 5 the 24th Division pierced American lines at Kochi and penetrated as far north as Tanabaru, but after 3 days of frantic and bitter fighting the Japanese invaders were annihilated by withering artillery, mortar and machine gun fire on all fronts, suffering devastating losses of over 5,000 lives and crippling the Japanese 32nd Army. Afterward, a chastened Gen. Ushijima called in Col. Yahara and said:
"Col. Yahara, as you predicted, this offensive has been a total failure. Your judgment was correct. You must have been frustrated from the start of this battle because I did not use your talents and skill wisely. Now I am determined to stop this offensive. Meaningless suicide is not what I want we will fight to the southernmost hill, to the last square inch of land, and to the last man. I am ready to fight, but from now on I leave everything up to you." (Yahara, The Battle for Okinawa, p. 41)
Gen. Ushijima ordered the 24th Division to revert to defensive attrition back to the Shuri defense lines.
On May 6 the U.S. 10th Army resumed its attack upon the Asa-Dakeshi-Gaja line, encountering a re-grouped 24th Division reinforced by service units pressed into combat service. The 1st and 6th Marine, 7th, 77th and 96th Divisions attacked with tanks and infantry, cave-by-cave, hill-by-hill meeting fierce resistance at every sector.
Artillery, mortar and flame-throwers were directed at pillboxes and caves, sending the defenders into retreat and hiding, then advancing troops up to the mouth of caves and pillpoxes, destroying them with demolition or napalm-gasoline fire and entombing the Japanese defenders within.
Gen. Ushijima concentrated all his defensive strength in the middle Shuri sector, against which Gen. Buckner ordered an all-out assault on May 11. For the next 18 days advances against the Shuri line was slow, bitterly fought and costly.
Key enemy defensive points Conical Hill (Gaja), Sugar Loaf Hill (Asato), Chocolate Drop Hill (Kochi), Dakeshi Ridge, Wana Ridge and Ishimmi Ridge all fell by May 21 but only after inflicting punishing losses on all American attacking units.
Then from May 22 heavy rains fell daily and continued for weeks, which became the enemy's best defense as the American offense got mired in the mud. During this time the Japanese air force launched its greatest aerial offensive sending 896 raids of suicide kamikaze planes crashing into American ships inflicting serious damage and bombing the Ie, Yontan and Kadena airfields, but losing almost 4,000 planes to American anti-aircraft fire.
The Fall of Shuri
By May 29, American 10th Army units had captured Naha on the west and Yonabaru on the east and beyond, setting the stage for the encirclement of Shuri in the center. The high command of Gen. Ushijima met and decided to withdraw from Shuri to the south to further prolong the battle and inflict continuing losses on American forces, rather than to make the final stand and battle at Shuri.
The order to withdraw issued May 24th and by May 29 Japanese Army Headquarters had abandoned Shuri, leaving small units to fight rear-guard actions. Gen. Ushijima succeeded in secretly withdrawing his defending army from Shuri before their retreat could be pinched off by advancing American forces. Overcoming suicidal enemy rear-guard action, the 77th and 96th Divisions completed the occupation of Shuri by May 31.
Shuri was levelled and left in complete ruin, after being pounded by 200,000 rounds of naval and artillery gunfire and aerial bombing. As of the retreat from Shuri by end of May, the Japanese army had been decimated by over 70,000 killed-in-action, and yielding only 9 prisoners who were badly wounded or unconscious. Very few Japanese prisoners were captured because:
"The Japanese soldier fought until he was killed. There was only one kind of Japanese casualty---the dead. Those that were wounded either died of their wounds or returned to the front lines to be killed. The Japanese soldier gave his all." (Okinawa: The Last Battle, p. 384)
The Last Stand
The final American attack was launched on June 1 under the rain and mud against the new Japanese defense line which stretched from Gushichan to Itoman and anchored on the high ground of the "Big Apple" (Yaeju-Dake) and Yuza-Dake.
The lightly defended Chinen Peninsula was overrun by June 4. On June 4 the 6th Marines landed on Oroku Peninsula, capturing Naha airfield, wiping out a pocket of Navy troops led by Admiral Minoru Ota who then committed hara-kiri, and advancing south toward Itoman.
The 7th and 96th Division assault on Hill 95 Escarpment (Hanagusuku) on June 6 was met with deadly fire from the entrenched defenders whom Ushijima had ordered "to defend to the last man" and this defensive stronghold was finally taken on June 11 only after the Japanese were burned out of their caves with streams of flaming napalm.
On June 10 tanks and infantry of the 7th and 96th Divisions attacked the defensive center of Yuza and Yaeju-Dake while Gen. Ushijima, faced with dwindling supplies and equipment and mounting casualties, ordered his troops to defend and hold the line "to the death." The First Marines advancing past Itoman faced murderous defensive fire from defenders on Yuza Peak and Kunishi Ridge, and were pinned down for days suffering heavy losses until supporting tank, air, naval and ground artillery fire systematically destroyed the last enemy resistance.
Yuza and Kunishi could be taken by the U.S. Marines only after 5 days of bitterest fighting and suffering some of the highest casualties of the Okinawa campaign.
Around this time the entrenched Japanese were not only bombarded by ceaseless U.S. naval guns but were showered with surrender leaflets and daily loudspeaker broadcasts in fluent Japanese from offshore craft urging:"Japanese soldiers. You fought well and proudly for the cause of Japan, but now the issue of victory or defeat has been decided. To continue the battle is meaningless. We will guarantee your lives. Please come down to the beach and swim out to us."
But these messages were ignored, and only a few swam out to offshore American ships. Then on June 17, General Buckner sent a message to General Ushijima which read:
"The forces under your command have fought bravely and well. Your infantry tactics have merited the respect of your opponents in the battle for Okinawa.
Like myself you are an infantry general, long schooled and experienced in infantry warfare. You must surely realize the pitiful plight of your defense forces. You know that no reinforcements can reach you. I believe, therefore, that you understand as clearly as I, that the destruction of all Japanese resistance on the island is merely a matter of days. It will entail the necessity of my destroying the vast majority of your remaining troops."
Col. Yahara wrote that "General Buckner's proposal for us to surrender was, of course, an affront to Japanese tradition. General Ushijima's only reaction was to smile broadly and say, 'The enemy has made me an expert on infantry warfare.'" (Yahara, The Battle for Okinawa, p. 136)
But in his innermost thoughts Col. Yahara pondered over the "Japanese tradition" of committing suicide rather than to surrender:
"In Japan, from the thirteenth century until the Meiji Restoration of the mid-nineteenth century, there are many examples where every soldier was killed in defense of the castle. In some cases only the lord of the castle committed suicide, while the soldiers (samurai) lived. In the early years of Meiji, Tokugawa supporters readily surrendered to the new Imperial Army. Since the Meiji Restoration, through the Sino-Japanese War, the Russo-Japanese War, and the China Incident of 1931, Japan had never lost a war. We also had never waged a war in which large forces were isolated from mainland support. Thus, not to be taken prisoner became a fixed principle---part of our military education.
Since the middle of the Greater East Asia War, most Japanese garrisons in the Pacific islands adhered to this supreme Japanese principle: 'Never surrender to the enemy.' Officers and men usually committed suicide, as a last resort to avoid the ultimate 'shame of capture. Our 32nd Army was now faced with this situation. Must one hundred thousand soldiers die because of tradition? From this point on it was but a battle to kill the remaining Japanese soldiers for nothing. We could cause the enemy little damage; they could walk freely on the field of battle. The war of attrition was over, and we would simply be asking the enemy to use this formidable power to kill us all." (Yahara; The Battle for Okinawa, p. 137-138)
The Battle Finally Ends
By June 17 the 10th Army forces penetrated and held all major positions along the last Japanese Gushichan-Itoman defensive line. The key high ground of Hill 153 near Madeera (Maehira) was taken by 7th Division troops from remnants of the disintegrating Japanese 32 Army now down to their last ammunition and supplies.
When the enemy counterattack to recapture Hill 153 ordered by Ushijima was decimated on June 18, organized Japanese resistance dissolved into disorganized mobs fighting desperately, determined to take every attacking American to death with them. They were faithfully following General Ushijima's last order which read:
"The battlefield is now in such chaos that all communications have ceased. It is impossible for me to command you. Every man in these fortifications will follow his superior officer's order and fight to the end for the sake of the motherland. This is my final order. Farewell." (Yahara, The Battle for Okinawa, p. 134)
Thousands of Japanese were holed up in caves around Madeera and Makabe defending fanatically, forcing the U.S. 5th Marines to fight on until June 21 to wipe out the survivors and to secure this last pocket of resistance.
Excerpts from "The Battle of Okinawa" courtesy of Ted Tsukiyama. Copyright is retained by Ted Tsukiyama. Photographs courtesy of U.S. Army Center of Military History.