Three days after “Little Boy” was dropped on Hiroshima, a bomb, code-named “Fat Man” was dropped on Nagasaki, Japan. Manhattan Project: The Atomic Bombing of Nagasaki, August 9, 1945
After problems with weather, a uranium implosion bomb (similar to the first atomic bomb, The Gadget, detonated on July 15th of that year) was dropped on the industrial city of Nagasaki. It was later determined that it was 21 kiloton equivalent explosion.
A small conventional raid on Nagasaki on August 1st had resulted in a partial evacuation of the city, especially of school children. There were still almost 200,000 people in the city below the bomb when it exploded. The hurriedly-targeted weapon ended up detonating almost exactly between two of the principal targets in the city, the Mitsubishi Steel and Arms Works to the south, and the Mitsubishi-Urakami Torpedo Works to the north.
Water line breaks hampered firefighting efforts, and the damage done to the two Mitsubishi plants was described as “spectacular.” Though the bomb was 40 percent larger than the Hiroshima bomb, it did less destruction. But the destruction it caused was still extreme.
The best estimate is 40,000 people died initially, with 60,000 more injured. By January 1946, the number of deaths probably approached 70,000, with perhaps ultimately twice that number dead total within five years. For those areas of Nagasaki affected by the explosion, the death rate was comparable to that at Hiroshima.
The day after Nagasaki was bombed, Japan surrendered – almost unconditionally.