National Geographic Samurai Sword: The blades of old samurai swords are sometimes carved with a single terrifying figure: the number of human bodies they have sliced in two with a single stroke. Indeed, each katana, or samurai sword, has its own unique story of not only a lethal past, but also an exquisite creation. Trace one blades beginnings to rural Japan, where a smelter prays to a Shinto shrine as a nearby mixture of charcoal and the purest iron sand is heated to over 1,000 degrees Celsius - until he shatters the furnace walls, releasing a blistering mass of steel. From fiery forging workshops to ferocious fighting schools, discover the mysterious process behind the creation of the sword that many experts call the most effective in the world. Generations of metalsmiths and warriors have worked for centuries to perfect this process of art and chemistry, trial and honor, discipline and devotion-all embodied in the razor-sharp blade of the katana sword.