Well, my impression that it was nothing in comparison with what the japs did to American prisoners. I gather that as the war wore on, our guys became more like the Japanese troops, because that was the only way to take them down. They were, after all, religious fanatics dying for a living god, the Emperor. Don’t waste lives trying to take them prisoners: just kill them
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I suggest Richard Tregaskis' "Guadalcanal Diary" (the book not the film). He makes it clear that the Marines learned pretty quick to kill the Japs twice after a few incidents wherein 'dead' Japs got up and killed incautious Marines. The Marines would walk the dead zone and put another bullet into every Jap body.
Another good book on the “no quarter” combat in the Pacific Theater
(probably should come with a parental advisory):
With the Old Breed: At Peleliu and Okinawa
by E.B. Sledge