"Fat Man" atom bomb. Actually this is just the bomb casing with all the dangerous nuclear guts removed. The 10,000 pound "Fat Man" was a type of plutonium bomb dropped on Nagasaki on August 9, 1945. The primary target, Kokura, was overcast that day so the "Fat Man" was dropped on its backup target, Nagasaki. Kokura is probably the luckiest city in the world. Japan surrendered a couple days later, making it unnecessary for the Allies to invade. The planned invasion of Kyushu, called Operation Olympic, would have been half again as big as the Normandy invasion. Had the first couple atom bombings been unsuccessful in making Japan surrender, as they nearly were not, the US planned to drop as many as fifty atom bombs on Japan. Three atom bombs each would have been dropped behind each of the three main landing beaches in Kyushu to annihilate the defenses. Japan would have been one big cinder.