The Japanese sword combines unbreakability, rigidity, and lethal cutting power, and it is in the resolution of these conflicting practical requirements that it emerges as a triumph of the forger's art. The mystique of the sword lingers on in our age of mechanized combat, but the aesthetic qualities for which swords are most valued by collectors today-the liveliness of the metal "skin," the confidence in every aspect of the design, the scrolling temper-line,...