Since you are interested in the martial arts of Japan and weaponry, you might be interested in checking out this special produced by American Public Television, NOVA Secrets of the Samurai Sword.

http://www.pbs.org/wgbh/nova/samurai/

I was so saddened to hear that many of the most famous swords were originally nodachi that were cut down in size, like the Honjo Masamune. But I suppose, a weapon has to suit it's time, ne?