The Hiroshima bomb was dropped on August 6, 1945, and the Nagasaki bomb on August 9, 1945.
At that time, Japan had succeeded in producing uranium hexafluoride (UF6), while the United States had not yet completed the process.

Japan succeeded in testing actual atomic bombs during World War II.

Atomic bomb that could not be loaded on bombers

At the time of World War II, Japan was unable to produce an atomic bomb large enough to be loaded on a bomber such as the B-29.

The Hiroshima and Nagasaki atomic bombs were ground detonations.

As mentioned above, "atomic bombs dropped from bombers" is a fiction. In reality, the atomic bombs were actually detonated by bombs placed on the ground.
There is no way that the U.S. could have installed them during wartime. Then, who installed the bombs?

The owner of the atomic bomb patent is the Emperor of Japan.

https://ri4jp-web-fc2-com....