Iwo Jima translates as ‘Sulfur Island’, a name that gives some impression of its foreboding nature. Remote, volcanic and inhospitable at the best of times, on 19 February 1945, Iwo Jima presented U.S. Marines with an especially unwelcoming landscape.
With American forces set to mount an amphibious attack on the island, Japan resolved to ensure that the engagement would be a long, bloody and dispiriting one, plotting to defend in depth and make the inhospitable terrain work to their advantage. 36 days of World War Two’s most intense fighting lay ahead.
1. The Japanese defence was commanded by Lieutenant General Tadamichi Kuribayashi
Kuribayashi’s radical departure from established Japanese strategy shaped the engagement, leading to a drawn out, punishing battle. Prior to Iwo Jima, Japan had defended more directly, opting to face U.S. troops on the beaches in the Gilbert, Marshall, and Mariana Islands. This time Kuribayashi opted to hang back and defend from deeper positions, deliberately delaying the Americans and inflicting as many casualties as possible. In doing so he hoped to damage U.S. spirits and buy more time for Japan to prepare for a looming invasion.
2. The Japanese constructed an elaborate network of tunnels
Kuribayashi’s deep defence strategy involved the construction of 11 miles of fortified tunnels that connected 1,500 rooms, artillery emplacements, bunkers, ammunition dumps, and pillboxes. This enabled Japanese soldiers to conduct their stubborn defence from concealed positions and limited the impact of American air and naval bombardment. Kuribayashi ensured that every part of the island was subject to Japanese fire.
3. America’s pre-landing bombardments were largely ineffective
Ahead of the amphibious assault the U.S. launched a three-day bombardment. This was significantly shorter than the ten-day heavy shelling bombardment Maj. General Harry Schmidt had requested and had limited impact due to the Japanese troops being so thoroughly dug-in.
4. The black beaches that faced American troops were far more challenging than anticipated
U.S. plans seriously underestimated the beach terrain their landing force would meet at Iwo Jima. Rather than the ‘excellent’ beaches and ‘easy’ progress predicted by planners, they faced black volcanic ash that failed to provide safe footing and steep 15-foot high slopes.
5. Kuribayashi waited until the beach was packed with U.S. forces before unleashing the full force of his heavy artillery
The modest response to their beach landings led the U.S. Navy to presume that their bombardment had seriously impaired Japanese defences. In fact, the Japanese were holding back. When the beach was full of troops and landing craft Kuribayashi signalled the commencement of a heavy artillery assault from all-angles, exposing the invading force to a nightmarish barrage of bullets and shells.
6. The Japanese tunnel system allowed them to reoccupy bunker positions
U.S. forces were frequently surprised to find that bunkers they’d ‘cleared’ with grenades or flamethrowers were swiftly reoccupied thanks to the network of tunnels.
7. Flamethrowers became a key weapon for the U.S. invaders
The M2 flamethrower was considered by commanders to be the single most effective weapon in the Iwo Jima engagement. Each battalion was assigned a flamethrower operator and they became the most effective means of attacking Japanese troops in pillboxes, caves, buildings and bunkers.
8. Navajo code talkers played a vital part
From May 1942, the U.S. utilised Navajo code talkers. Because Navajo grammar is so complex, mutual intelligibility and codebreaking is virtually impossible. The speed and accuracy of the Navajo code talkers was indispensable at Iwo Jima – six code talkers sent and received over 800 messages, all without error.
9. Iwo Jima was a costly victory for the U.S.
American victory came at a grave cost. Over the course of the 36-day engagement there were 26,000 U.S. casualties, including 6,800 dead. This makes Iwo Jima the only battle of the Pacific War in which U.S. casualties outnumbered Japanese, although the number of Japanese soldiers killed (18,844) was almost three times greater than the U.S. death count.
10. An unprecedented number of U.S. Marines were awarded a Medal of Honour
The ferocity of the fighting at Iwo Jima led to 27 U.S. Marine Corps and Navy personnel being awarded a Medal of Honour, the highest military decoration in America, for their bravery during the engagement. That’s 28% of the 82 Medals of Honour awarded to Marines over the course of the entire Second World War.