Fat Man (atomic bomb)

Fat Man was the codename of the second atomic bomb used against Japan in World War II. It was air-dropped onto Nagasaki on 9 August 1945, destroying the city in the same way as Hiroshima in the earlier strike. The Japanese surrendered five days later to end the Second World War.

The Manhattan Project had detonated an identical device in the Trinity Test at White Sands, New Mexico, to confirm that the technology actually worked. It was a plutonium implosion device, with an energy yield of approximately 12 kilotons of TNT equivalent. It was also designated as "Mark III" by the United States Army. Between 1947 and 1950, during the post-war era, 120 Fat Man bombs were produced and available for service.