Today is often considered VJ-Day because it was the day in 1945 that the Japanese surrender was announced, although Sept. 2 was the actual surrender date.
Postwar Cold War strategy required a fairly rapid rehabiliation of Japan, and Gen. Douglas McCarthur found it expedient to take a lenient attitude towards Japanese officials as he rebuilt Japan as a modern democratic state -- successfully.
Still, it's worth remembering that the Japanese World War II record was dismal as far as conduct towards civilians and prisoners were concerned. The record of wartime atrocities is large, but what's not well-known is that the atrocities didn't even end on VJ-Day. Sadly more than 100 POWs were executed AFTER VJ-Day, evidently in an attempt to preclude war crimes prosecutions by eliminating witnesses. The effort failed, as apparently the murders were not comprehensive enough to succeed and a number of Japanese officers were hanged.
No matter how much I learn about World War II there are always surprises as my studies continue.