"Japan's barbarism in the months and years leading up to the atom bombs was unparalleled.
From the invasion of China in 1937 to the end of World War II, the Japanese military regime murdered near 3,000,000 to over 10,000,000 people, most probably almost 6,000,000 Chinese, Indonesians, Koreans, Filipinos, and Indochinese, among others, including Western prisoners of war."
https://hawaii.edu/powerkills/SOD.CHAP3.HTM
Those two bombs shocked Japan and ended a war that otherwise would have seen the loss of countless Asian lives -- including the lives of many Japanese. Sadly they were too late to save the lives of millions of Asians raped and murdered by the Japanese war machine.