Why did military planners believe that an attack on japan would be much more costly and dangerous than the d day invasion and eventual defeat of Germany?

Answer 1

Unlike the Germans, the Japanese soldiers had proven themselves to be fanatical in war. Prefering to take the offensive when all hope was gone. Their intelligence had picked up that the Japanese military was training civilians (women, children, old people) to act in the defense of the country. This was in addition to the kamikaze planes and motorboats manned by the regular Japanese military. This would have meant a MASSIVE slaughter of Japanese if an invasion took place as well as unheard of U.S. casualties. At least with your typical German soldier and civilian they knew when it was time to give up or pull out.
In dollars and sense the logistics would have been about the same. The real cost was the anticipated death toll for Allied soldiers and the Japanese civilian population. At every battle the Japanese proved they would die for their emperor and their homeland. They had been taught that if they were captured by allied forces they would be tortured, beaten and raped to a man, woman or child. So our military planners knew that Our soldiers were going to have to shoot and kill kids and the elderly if we invaded Japan and that our men would hesitate putting their own lives at risk. Whether using the "BOMB" was the right choice or not will be debated forever.

Answer 2

There are 3 reasons..... 1. Americas allies are closer to Germany. 2. Germany controlled almost all of Europe. 3. Japanese people were suicidal and would kill themselves for Japan.