4. The Battle The Battle February 19, 1945 The U.S sent more marines to Iwo Jima than any other battle. (110,000) 21,000 Japanese soldiers defended the island from within a vast network of underground tunnels and bunkers. Many Japanese gunners took position on Mt. Suribachi, where they could take aim at American soldiers coming in from every landing beach. Because of the island’s loose volcanic soil, Marines were unable to dig fox holes are any other possible defense against the rain of bullets. Every Marine on the island was exposed. The battle was brutal and confusing. Over 100,000 men were battling on a 7.5 mile long island. The Americans won the war inch-by-inch. Flamethrowers, hand grenades, and napalm were found to be most useful against the Japanese defending from underground. The battle lasted 35 days.