Why were atomic bombs dropped only in nagasaki and why hiroshima out of the whole of japan?

Answer 1

doesn't really answer your question

during the closing stages of the war against Japan, japan was extensively fire bombed by the Americans. all the major industrial cities were basically destroyed. Hiroshima kokura and nagasaki all had something in common

1. they were coastal
2. they were surrounded by mountains
3. they had minor military factories and ports
4. they had approximately 250,000 in population

these cities were left basically untouched by the Americans during all of the bombings of japan. why?

1. being surrounded by mountains it would contain the blast
2. having ports and military targets gave a good reason for bombings
3. if you bombed Tokyo or Osaka you would kill a million plus civilians (not acceptable in public opinion) but believe it or not 250,000 is acceptable.

they were dropped on those cities because they were perfect test sites for the atom bomb. you may ask what has kokura to do with it. kokura was the secondary target for the hiroshima bombing and the primary target for the nagasaki bombing. the bombs need to be dropped in fine weather for bombardier accuracy and to take arial phots of the effects. luckily for the people of kokura on the day of the hiroshima bombing it was fine in hiroshima and on the day of the nagasaki bombing it was overcast in kokura so they missed out.

i hope this answered your question.

Those two bombs were enough to kill thousands and thousands of people and to bring Lapan to it knees.