The Battle of Iwo Jima was fought from February 19 to March 26, 1945, during World War II (1939-1945). The American invasion of Iwo Jima came after Allied forces had island-hopped across the Pacific and had conducted successful campaigns in the Solomon, Gilbert, Marshall, and Mariana Islands. Landing on Iwo Jima, American forces encountered much fiercer resistance than expected and the battle became one of the bloodiest of the war in the Pacific.

Forces & Commanders

Allies

Japanese

Lieutenant General Tadamichi Kuribayashi

Colonel Baron Takeichi Nishi

23,000 men

Background

During 1944, the Allies achieved a series of successes as they island-hopped across the Pacific. Driving through the Marshall Islands, American forces captured Kwajalein and Eniwetok before pushing on to the Marianas. Following a victory at the Battle of the Philippine Sea in late June, troops landed on Saipan and Guam and wrested them from the Japanese. That fall saw a decisive victory at the Battle of Leyte Gulf and the opening of a campaign in the Philippines. As a next step, Allied leaders began developing plans for the invasion of Okinawa.

Since this operation was intended for April 1945, Allied forces were faced with a brief lull in offensive movements. To fill this, plans were developed for the invasion of Iwo Jima in the Volcano Islands. Located approximately mid-way between the Marianas and the Japanese Home Islands, Iwo Jima served as an early warning station for Allied bombing raids and provided a base for Japanese fighters to intercept approaching bombers. Additionally, the island offered a launching point for Japanese air attacks against the new American bases in the Marianas. In assessing the island, American planners also envisioned using it as a forward base for the anticipated invasion of Japan.

Planning

Dubbed Operation Detachment, planning for capturing Iwo Jima moved forward with Major General Harry Schmidt's V Amphibious Corps selected for the landings. Overall command of the invasion was given to Admiral Raymond A. Spruance and the carriers Vice Admiral Marc A. Mitscher's Task Force 58 were directed to provide air support. Naval transport and direct support for Schmidt's men would be given by Vice Admiral Richmond K. Turner's Task Force 51.

Allied air attacks and naval bombardments on the island had commenced in June 1944 and had continued through the remainder of the year. It was also scouted by Underwater Demolition Team 15 on June 17, 1944. In early 1945, intelligence indicated that Iwo Jima was relatively lightly defended and given the repeated strikes against it, planners thought it could be captured within a week of the landings (Map). These assessments led Fleet Admiral Chester W. Nimitz to comment, "Well, this will be easy. The Japanese will surrender Iwo Jima without a fight."

Japanese Defenses

The believed state of Iwo Jima's defenses was a misconception that the island's commander, Lieutenant General Tadamichi Kuribayashi had worked to encourage. Arriving in June 1944, Kuribayashi utilized lessons learned during the Battle of Peleliu and focused his attention on building multiple layers of defenses that centered on strong points and bunkers. These featured heavy machine guns and artillery as well as held supplies to allow each strong point to hold out for an extended period. One bunker near Airfield #2 possessed sufficient ammunition, food, and water to resist for three months.

Additionally, he elected to employ his limited number of tanks as mobile, camouflaged artillery positions. This overall approach broke from Japanese doctrine which called for establishing defensive lines on the beaches to combat invading troops before they could land in force. As Iwo Jima increasingly came under aerial attack, Kuribayashi commenced focusing on the construction of an elaborate system of interconnected tunnels and bunkers. Connecting the island's strong points, these tunnels were not visible from the air and came as a surprise to the Americans after they landed.

Understanding that the battered Imperial Japanese Navy would not be able to offer support during an invasion of the island and that air support would be nonexistent, Kuribayashi's goal was to inflict as many casualties as possible before the island fell. To this end, he encouraged his men to kill ten Americans each before dying themselves. Through this he hoped to discourage the Allies from attempting an invasion of Japan. Focusing his efforts on the northern end of the island, over eleven miles of tunnels were constructed, while a separate system honeycombed Mt. Suribachi at the southern end.

The Marines Land

As a prelude to Operation Detachment, B-24 Liberators from the Marianas pounded Iwo Jima for 74 days. Due to the nature of the Japanese defenses, these air attacks had little effect. Arriving off the island in mid-February, the invasion force took up positions. The American planned called for the 4th and 5th Marine Divisions to go ashore on Iwo Jima's southeastern beaches with the goal of capturing Mt. Suribachi and the southern airfield on the first day. At 2:00 AM on February 19, the pre-invasion bombardment commenced, supported by bombers.

Heading towards the beach, the first wave of Marines landed at 8:59 AM and initially met little resistance. Sending patrols off the beach, they soon encountered Kuribayashi's bunker system. Quickly coming under heavy fire from the bunkers and gun emplacements on Mt. Suribachi, the Marines began to take heavy losses. The situation was further complicated by the island's volcanic ash soil which prevented the digging of foxholes.

Pushing Inland

The Marines also found that clearing a bunker did not put it out of action as Japanese soldiers would use the tunnel network to make it operational again. This practice would be common during the battle and led to many casualties when Marines believed they were in a "secure" area. Utilizing naval gunfire, close air support, and arriving armored units, the Marines were slowly able to fight their way off the beach though losses remained high. Among those killed was Gunnery Sergeant John Basilone who had won the Medal of Honor three years earlier at Guadalcanal.

Around 10:35 AM, a force of Marines led by Colonel Harry B. Liversedge succeeded in reaching the island's western shore and cutting off Mt. Suribachi. Under heavy fire from from the heights, efforts were made over the next few days to neutralize the Japanese on the mountain. This culminated with American forces reaching the summit on February 23 and the raising of the flag atop the summit.

Grinding on to Victory

As fighting raged for the mountain, other Marine units battled their way north past the southern airfield. Easily shifting troops through the tunnel network, Kuribayashi inflicted increasingly severe losses on the attackers. As American forces advanced, a key weapon proved to be flamethrower-equipped M4A3R3 Sherman tanks which were difficult to destroy and efficient at clearing bunkers. Efforts were also supported by the liberal use of close air support. This was initially provided by the Mitscher's carriers and later transitioned to the P-51 Mustangs of the 15th Fighter Group after their arrival on March 6.

Fighting to the last man, the Japanese made superb use of the terrain and their tunnel network, constantly popping out to surprise the Marines. Continuing to push north, the Marines encountered fierce resistance at the Motoyama Plateau and nearby Hill 382 during which the fighting bogged down. A similar situation developed to the west at Hill 362 which was riddled with tunnels. With the advance halted and casualties mounting, Marine commanders began changing tactics to combat the nature of the Japanese defenses. These include assaulting without preliminary bombardments and night attacks.

Final Efforts

By March 16, after weeks of brutal fighting, the island was declared secure. Despite this proclamation, the 5th Marine Division was still fighting to take Kuribayashi's final stronghold at the northwest tip of the island. On March 21, they succeeded in destroying the Japanese command post and three days later closed the remaining tunnel entrances in the area. Though it appeared that the island was fully secured, 300 Japanese launched a final assault near Airfield No. 2 in the middle of the island on the night of March 25. Appearing behind the American lines, this force was ultimately contained and defeated by a mixed group of Army pilots, Seabees, engineers, and Marines. There is some speculation that Kuribayashi personally led this final attack.

Aftermath

Japanese losses in the fighting for Iwo Jima are subject to debate with numbers ranging from 17,845 killed to as high as 21,570. During the fighting only 216 Japanese soldiers were captured. When the island was declared secured again on March 26, approximately 3,000 Japanese remained alive in the tunnel system. While some carried on limited resistance or committed ritual suicide, others emerged to scavenge for food. US Army forces reported in June that they had captured an additional 867 prisoners and killed 1,602. The final two Japanese soldiers to surrender were Yamakage Kufuku and Matsudo Linsoki who lasted until 1951.

American losses for Operation Detachment were a staggering 6,821 killed/missing and 19,217 wounded. The fighting for Iwo Jima was the one battle in which American forces sustained a greater number of total casualties than the Japanese. In the course of the struggle for the island, twenty-seven Medals of Honor were awarded, fourteen posthumously. A bloody victory, Iwo Jima provided valuable lessons for the upcoming Okinawa campaign. In addition, the island fulfilled its role as a waypoint to Japan for American bombers. During the final months of the war, 2,251 B-29 Superfortress landings occurred on the island. Due to heavy cost to take the island, the campaign was immediately subjected to intense scrutiny in the military and press.