And don't forget how many Japanese (military and civilian) would have died in the invasion and eventual blockade of the islands. Mass starvation, perpetual bombing runs and destruction. The WHOLE continent of Japan would have been destroyed with millions of dead.
Also, it was clear that the Japanese were willing to fight to the death, ie, the kamikaze if their emperor told them to do so.
I never knew Japan was a continent.
Not quite. The view of the Japanese military hardliners was that the atomic bombing [pico-dan] of Japanese cities had driven the divine emperor insane, and that their obligation girito protect his honor was to kill the emperor to prevent the dissemination of his 15 August gyokuon-hōsō Imperial Rescript of Surrender, which they viewed would dishonor him, and then die themselves in battle.
As an example into their mindset: if President Obama were to unilaterally surrender to the Iranians and agree to have the United States submit to a Sharia law, what do you think the reaction of most Americans, and hopefully most of our military, would be?