During the Battle of Iwo Jima in the Pacific War, around 20,000 Japanese soldiers were killed in the battle, most of them in cave-like tunnels. The American army used grenades, flamethrowers and sandbag bombs to completely destroy the Japanese army's cave positions.

 　During the Battle of Iwo Jima in the Pacific War, around 20,000 Japanese soldiers died in the battle in the cave-like tunnel. The American army used grenades, flamethrowers and sandbag bombs to destroy the Japanese army's cave positions one by one. The Battle of Iwo Jima became an extremely fierce battle with a high casualty rate in American military history. Over the first five days, the average daily casualty rate was over 1,200, with one in three of the Marines who landed dying or being wounded. In the first 50 hours, the American casualties exceeded 3,000.

　　The Japanese army waged a fierce defense for over five weeks after the American army landed on Iwo Jima on February 19, 1945. The Japanese army was annihilated through relentless close-quarters attacks from caves and other strongholds. The annihilation of the Japanese army through suicide attacks terrified the Allied forces and the American people. The Allied forces feared that a far greater number of casualties would be incurred in the invasion of the Japanese mainland.

　　In the Battle of Iwo Jima, the number of casualties among the American offensive forces exceeded those of the Japanese defensive forces. The American forces suffered a staggering number of casualties, with approximately 7,000 of the landing force and fleet personnel killed in action and 19,000 wounded. At the end of the battle, the combat capability of each American division was less than 50%.

　　This was suggested in the book “History of the Pacific War” written by Admiral C.W. Nimitz, Commander of the US Pacific Fleet at the time. The statistics for the number of Japanese and American soldiers killed and wounded in action were given as rough estimates. The current confirmed number is 20,129, including 12,723 from the Army and 7,406 from the Navy. In addition, dozens of the residents of Iwo Jima at the time were conscripted into the Japanese army and unable to evacuate, and they shared the fate of the army and were killed in action.

　　The number of American military personnel killed in the Battle of Iwo Jima was 6,821 in total: 5,931 Marines, 881 Navy personnel, and 9 Army personnel. The Japanese army suffered 12,850 casualties, and the navy suffered 7,050 casualties, giving a total of 19,900 casualties for the Japanese army.

　　The number of battle casualties in the Battle of Iwo Jima was 21,865 in total, with 19,920 battle casualties among the US Marine Corps, 1,917 battle casualties among the Navy, and 28 battle casualties among the Army. 736 Japanese Army personnel and 736 Navy personnel were wounded, for a total of 1,033 wounded. The number of casualties was 28,686 for the American forces and 20,933 for the Japanese forces, with the American offensive forces outnumbering the Japanese defensive forces by 7,753.