Mass rapes of Chinese women, Korean camp girls, and Australian nurses. They were absolutely brutal.
If we didn't firebomb and drop the atomic bombs, we would have invaded and killed 20MM+ civilians in the process. Because all the civilians would have resisted to the end. They almost did. The 3rd bomb was headed to Tokyo and with Hirohito dead, they would have resisted forever — until they all died.
And by the way, the Soviets landed its first troops on August 18, 1945. Think about what would have happened with a divided Japan.
It's good that the Americans have forgiven the Japanese.