World War II in the Pacific was fought with intense ferocity and great cruelty. Propaganda on both sides portrayed the enemy as inhuman and worthy of extermination. Atrocities committed against civilian populations and prisoners of war convinced soldiers that taking or becoming a prisoner was not an option, it was literally "kill or be killed." Here are some recollections from soldiers on both sides that attest to the horror of war in the Pacific.
American
"The war I knew was totally savage ... The Japanese fought by a code they thought was right: bushido. The code of the warrior: no surrender. You don't really comprehend it until you get out there and fight people who are faced with a hopeless situation and will not give up. If you tried to help one of the Japanese, he'd usually detonate a grenade and kill himself as well as you. To be captured was a disgrace. To us, it was impossible, too, because we knew what happened in Bataan [Bataan Death March]."
"You developed an attitude of no mercy because they had no mercy on us. It was a no-quarter, savage kind of thing. At Peleliu, it was the first time I was close enough to see one of their faces. This Jap had been hit. One of my buddies was field-stripping him for souvenirs. I must admit it really bothered me, the guys dragging him around like a carcass. I was just horrified. This guy had been a human being. It didn't take me long to overcome that feeling. A lot of my buddies hit, the fatigue, the stress. After a while the veneer of civilization wore pretty thin."
"I've seen guys shoot Japanese wounded when it was not necessary and knock gold teeth out of their mouths."
— E.B. Sledge