Now whether Japan would have surrendered even if the US had not nuked it, is a matter that's still hotly disputed up until this day, but what is not contested is just how murderous, fanatical and insane Japan and the Japanese people were before and during WW2.
During WW2, Japan was led by the ruthless Emperor Hirohito who was a close ally of Nazi Germany, and even before Pearl Harbor and before WW2 had even begun, Japan had already been at war with almost half of Asia.
People tend to forget that Imperial Japan was a despotic murderous regime, intent on expanding, murdering, pillaging and raping anything in its path, all in the name of their emperor Hirohito. From 1937 and up until its surrender Japan and its emperor were responsible for the deaths of over 20,000,000 people, the majority of whom were Chinese.
The Japanese reign of terror and insanity, with its inhumane crimes against the local population, mirrored those of Nazi Germany's in Europe.
For example, in 1937 Japanese imperial forces occupied Nanking, the capital of the Chinese republic, and commenced a six weeks orgy of destruction, massacres and rape of the local Chinese population.
At one point the Japanese had contests between themselves, of who could behead the most Chinese civilians, or rape the most Chinese women, etc… etc…
After six weeks of hell on earth, the Japanese murdered up to 300,000 people, raped up to 80,000 women and left Nanking a pile of ruins, all in the name of their beloved emperor Hirohito.
The death toll in Nanking exceeded that of the atomic blasts of Hiroshima and Nagasaki combined, but I wonder how many people today, who know about Hiroshima and Nagasaki, know about Nanking?
The Japanese also conducted horrendous medical experiments on innocent people and prisoners war and, what seems as something unbelievable but has been documented extensively, even ate their POWs.
So while the issue of whether nuking Japan was necessary and whether it was the cause for its surrender might be disputed, what is not disputed was the need to stop Imperial Japan, and its crazy, bloodthirsty, psychopathic, murderous emperor Hirohito, who was one of the greatest and unacknowledged villains of modern history.
Read more about Japan's emperor Hirohito: http://www.dispropaganda.com/#!Emperor-Hirohito-historys-greatest-unacknowledged-war-criminal/c10cg/5723388e0cf2d19e2972bf81