In the just-released film "Unbroken," as in real life, U.S. Army Air Corps Lt. Louis Zamperini was beaten, starved and forced to work as a slave laborer by his Japanese captors.

Things could have been worse. Like some other war prisoners held by the Japanese, Zamperini could have been used in biological warfare experiments. Or vivisected. Or beheaded, with parts of his body then eaten by his captors.

As the historian Daqing Yang notes, nine out of 10 American POWs who died in captivity in World War II did so at the hands of the Japanese.