Permanent Exhibit

Okinawa and the Atomic Bomb Exhibit

This exhibit is a part of our permanent collection and can be seen with our General Admission tickets.


Okinawa, the bloodiest battle of the Pacific War, started on April 1, 1945, and was intended to set the stage for the U.S. invasion of mainland Japan. The staggering loss of life in this battle gave insight into the likely losses of an invasion of Japan would cost. Our new president Harry S. Truman learned that we had developed the atomic bomb and was forced to make the decision to use the bomb(s) or continue with the invasion. The actual bomb casing and the exhibit provide insight into the war’s end.


Stretching southwesterly from Japan are the Ryukyu Islands, the largest of which is Okinawa, just under 400 miles from Kyushu. Okinawa would be the last step prior to the invasion of the Japanese home islands scheduled for November 1945, and March 1946.

The Battle of Okinawa may be divided into two parts: the land battle and the battle at sea. Waging the ground campaign would be the Allied Tenth Army, under the command of Lieutenant General Simon Bolivar Buckner, Jr., and consisting of 3 Marine divisions and 4 Army infantry divisions. The Navy deployed its powerful Fifth Fleet under the command of Admiral Raymond Spruance. The Japanese fielded the 32nd Army, under the command of Lieutenant General Mitsuru Ushijima, consisted of 3 infantry divisions and several mixed brigades.

The Japanese strategy did not call for stopping the Allies at Okinawa. Instead, the Japanese sought to make the campaign to take the island so costly the Allies would sue for peace before launching any further invasions, especially of the home islands.

Invasion planners set L-Day at Okinawa for 1 April 1945, Easter Sunday. Before the end of the day, over 50,000 troops and their equipment had been put ashore with little to no resistance. Waiting along with a series of well-defended lines, over 100,000 Japanese infantrymen waited. By the middle of June, the Allies had forced the remnants of the Japanese 32nd Army to the southern peninsula. By 22 June, the Allies declared Okinawa secure.

Meanwhile, offshore, the Fifth Fleet waged a deadly war against the dreaded kamikazes. By 30 April, twenty American ships had been sunk and 157 damaged. Due to the strain and length of the campaign, Admiral Nimitz switched commanders, replacing Admiral Spruance with Admiral Halsey so Spruance could rest and recuperate.

The Okinawa exhibit features several interactives including a table-top map summarizing the campaign, an oral history kiosk where visitors may hear about the battle from survivors, and a computer interactive offering maps, photos, orders of battle, and more. Visitors will also see inside a destroyer’s combat information center, view Marine PFC Eugene B. Sledge’s uniform, and see the scoreboard from USS Hugh W. Hadley (DD-774), a destroyer that shot down over 20 kamikazes in 90 minutes before being hit.

Sailors kept count of the Japanese planes shot down by the destroyer USS Hugh W. Hadley, 23 of which were downed in less than two hours while serving as a picket ship off Okinawa on May 11, 1945.

A Terrible New Weapon

From Potsdam, the United States, the United Kingdom, and China issued the Potsdam Declaration in July 1945, in which the Empire of Japan was given an ultimatum: surrender unconditionally or face prompt and utter destruction. The Empire of Japan ignored the message as the military strategy called for making continued fighting so costly to the Allies that the US would sue for peace instead of demanding unconditional surrender.

President Harry Truman, newly installed in office after President Roosevelt passed away suddenly in April 1945, had not been briefed on the development of atomic weapons. After considering the estimated casualties to US servicemen in an invasion of the Japanese home islands, President Truman authorized the use of atomic weapons.

The Army Air Forces delivered two to Japan: one detonated on 6 August over Hiroshima, the second over Nagasaki on 9 August. Emperor Hirohito overruled all militarist opposition to continue the fight and announced the Empire’s willingness to accept the terms outlined in the Potsdam Declaration. Japan surrendered on 15 August 1945 and made it official aboard USS Missouri on 2 September. World War II was at an end.

At the National Museum of the Pacific War, visitors will see an atomic bomb casing. The casing on display is of the Fat Man design, used at Nagasaki. This casing is one of seven manufactured during the war and available in case the US had to deliver further atomic attacks. This casing came to the museum from the US Department of Energy.

Atomic Bomb Casing donated by US Department of Energy