American casualties exceeded Japanese on this volcanic island — the only Pacific battle where that happened. The Japanese commander built 18 miles of tunnels and planned to die in them.
Iwo Jima was a sulfurous, volcanic island barely 8 square miles in size, with no civilian population and no natural resources. Its strategic value was its location: airfields that Japanese forces could use to intercept B-29 bombers attacking Japan, or that Americans could use to escort those bombers. Both sides understood what it was worth. Japan had 20,000 men on the island and had spent months turning it into a fortress.
Japanese commander Tadamichi Kuribayashi had rejected the tactics that had failed on other Pacific islands — banzai charges and beach defense. Instead he dug. His garrison constructed 18 kilometers of tunnels connecting hundreds of bunkers, pill boxes, and cave positions, many blasted from solid volcanic rock. Japanese soldiers would let the Americans land, then emerge from the tunnels to fight them in prepared positions that air and naval bombardment couldn't reach.
On February 19, 1945, 30,000 Marines hit the beaches of Iwo Jima. For the first 30 minutes, there was almost no opposition — then the island exploded with fire from every direction. The black volcanic sand made it nearly impossible to dig cover; Marines were pinned on the beach while shells and bullets swept in from positions they couldn't see. In the first days alone, casualties were catastrophic.
On February 23, four days into the battle, a small patrol reached the summit of Mount Suribachi, the island's dominant volcano, and raised a small American flag. A larger flag was raised later, photographed by Joe Rosenthal in an image that became one of the most iconic photographs in American history and won the Pulitzer Prize. Three of the six men raising that flag would be dead within a month.
The battle lasted 36 days. Marines cleared the tunnels with flamethrowers, demolitions, and infantry fighting in darkness and confined spaces against defenders who knew every passageway. Of the 20,933 Japanese defenders, 18,375 were killed. Only 216 were captured — the rest died fighting, were sealed in their tunnels, or disappeared into the island's cave system. Two Japanese soldiers hid and didn't surrender until 1949.
American casualties totaled 28,698 — 6,821 killed and 19,217 wounded. It was the only battle in the Pacific where American casualties exceeded Japanese, and the total cost shocked American military planners. Planning for the invasion of Japan, they calculated casualty estimates in the millions — a calculation that would weigh heavily on the decision to use the atomic bomb.