By 1945 Japan had no offensive capability, they lacked fuel for warships and pilots for aircraft. Kamikaze don't win wars, they just stave off defeat for a little while. In July and August 1945 US carrier aircraft bombed and strafed everywhere in Japan at will with almost no opposition. The end was coming soon one way or another.
The problem was 'the other' with them vowing to fight to the death. Each man, rooted out one by one. Lots of our soldiers would have died.
This assumes that an invasion was necessary. Given the fact that Japan was reaching out to the USSR to surrender before the USSR entered the Pacific theater, something Japan knew they couldn't survive, no invasion was necessary to end the war.
We could chose to believe you over them man that made the decision but you haven't explained why we should.
Harry S Truman’s Decision to Use the Atomic Bomb (U.S. National Park Service)
What Did Harry S Truman Have to Say About His Decision to Use the Atomic Bomb?
At the time, the president seemed conflicted over his decision. The day after the Hiroshima bomb was dropped, Truman received a telegram from Senator Richard B. Russell of Georgia, encouraging the president to use as many atomic bombs as possible on Japan, claiming the American people believed “that we should continue to strike the Japanese until they are brought groveling to their knees.” Truman responded, “I know that Japan is a terribly cruel and uncivilized nation in warfare but I can't bring myself to believe that because they are beasts, we should ourselves act in that same manner. For myself I certainly regret the necessity of wiping out whole populations because of the ‘pigheadedness’ of the leaders of a nation, and, for your information, I am not going to do it unless absolutely necessary.”