The Japanese military was determined to inflict a casualty rate so high that the U.S. government would give up its demand that Japan surrender unconditionally.
The United States Navy subjected the island to an unprecedented bombardment and, according to historian Samuel Eliot Morison, "In no previous operation in the Pacific had naval gunfire support been so effective as at Iwo Jima.
"[1] Nonetheless, Japanese artillery and machine-gun fire were extremely effective because the underground bunkers were so strong, only a direct hit by a bomb or naval shell could knock one out.
United States Pacific Fleet Admiral Chester W. Nimitz HQ at Pearl Harbor Expeditionary Troops (Task Force 56) Lieutenant General Holland M. "Howlin' Mad" Smith[a] V Amphibious Corps Major General Harry Schmidt Left landing area (Green and Red Beaches): Right landing area (Yellow and Blue beaches): Floating reserve: Lieut.
General Tadamichi Kuribayashi, commanding Colonel Tadashi Takaishi, chief of staff 21,060 total men under arms Army Navy Orders of battle involving United States Marine forces in the Pacific Theatre of World War II: