April 1, 1945 – On Okinawa, American forces launch Operation Iceberg, the invasion of Okinawa. Two corps of the US 10th Army (General Buckner) land in the area of Hagushi, in the southwest of the island.
US Task Force 51 (Admiral Turner) provides the 1,200 transports and landing ships including seven Coast Guard-manned transports, 29 LSTs, the cutters Bibb and Woodbine, and 12 LCI(L)s, with over 450,000 Army and Marine Corps personnel embarked. The troops landed are from US 3rd Amphibious Corps (Geiger) with US 6th and 1st Marine Divisions, on the left or northern flank, and 24th Corps (Hodge) with US 7th and 96th Infantry Divisions, on the right or southern flank. On land, US forces encounter almost no resistance on the first day and establish a beachhead three miles deep and nine miles wide. (Okinawa is 70 miles long and a maximum of 10 miles wide.) Kadena and Yontan airfields are captured. Japanese forces on the island, consisting of the 130,000 troops of the Japanese 32nd Army (General Ushijima), are entrenched in concealed positions and caves, mostly to the south of the American landing area along the Shuri Line. (There are also 450,000 civilians on the island.) At sea, US TF58 and TF54 as well as the British Pacific Fleet conduct air and naval bombardments. Japanese conventional and Kamikaze air strikes hit the battleship USS West Virginia, and the carrier, HMS Indomitable, along with eight other ships.
The Battle of Okinawa, codenamed Operation Iceberg, was fought on the Ryukyu Islands of Okinawa and was the largest amphibious assault in the Pacific War of World War II. The 82-day-long battle lasted from early April until mid-June 1945. After a long campaign of island hopping, the Allies were approaching Japan, and planned to use Okinawa, a large island only 340 mi (550 km) away from mainland Japan, as a base for air operations on the planned invasion of Japanese mainland (coded Operation Downfall). Four divisions of the U.S. 10th Army (the 7th, 27th, 77th, and 96th) and two Marine Divisions (the 1st and 6th) fought on the island. Their invasion was supported by naval, amphibious, and tactical air forces.
The battle has been referred to as the “typhoon of steel” in English, and tetsu no ame (“rain of steel”) or tetsu no bōfū (“violent wind of steel”) in Japanese. The nicknames refer to the ferocity of the fighting, the intensity of kamikaze attacks from the Japanese defenders, and to the sheer numbers of Allied ships and armored vehicles that assaulted the island. The battle resulted in the highest number of casualties in the Pacific Theater during World War II. Based on Okinawan government sources, mainland Japan lost 77,166 soldiers, who were either killed or committed suicide, and the Allies suffered 14,009 deaths (with an estimated total of more than 65,000 casualties of all kinds). Simultaneously, 42,000-150,000 local civilians were killed or committed suicide, a significant proportion of the local population. The atomic bombings of Hiroshima and Nagasaki caused Japan to surrender less than two months after the end of the fighting on Okinawa.