In Europe, some lords and their knights even demanded the right of first sex with a bride on her wedding day, before she got to sleep with her bridegroom. (You see this happen in the movie, Brave Heart, where an English knight takes the woman of a Scottish peasant.)

And in Japan, a Samurai who wanted to test out a new sword had the right to stand at a crossroads and kill the first innocent peasant who walked by. Not that they all did that, but they had the "right" do do so. It was more common to test out the sword on a convicted criminal instead.

In Europe, a Knight was only chivalrous towards females of his own class. The peasants meant nothing to them, remember... And in Japan women have always been treated differently than the men.

Traditionally the Japanese (and other Asian peoples) have never taken prisoners unless they wanted them for slave labor. It's a practical viewpoint, because prisoners are mouths to feed and they have to be guarded. They can be troublesome.

The Europeans have a tradition of taking prisoners only because they used to hold them to ransom.

Prisoners of War were sold back to their families, who had to sell everything they owned and come up with one quarter of the value of the prisoner's estate. That's the only reason European soldiers took prisoners... It was for the ransom they could extract.

If you couldn't convince your captors you were rich and worth keeping, they'd just slit your throat.

There were no P.O.W. camps in those days, a prisoner would be another mouth to feed and they would have to be guarded as well... A lot of trouble for anyone, and they wouldn't do it out of charity.

The phrase "Give No Quarter!" meant the soldiers were too busy at that time to think about ransom and taking prisoners... Pillaging, looting and raping were perks that came with the job of being a soldier back then. Often that was the only way they got paid.

The idea of a Geneva Convention is only very recent, and to my knowledge no Asian country ever signed a part of it.