The samurai sword is one of the greatest fighting weapons ever invented. Used by the vaunted medieval fighters of Japan, the sword was produced by a painstaking process of smelting iron from ore. Combined with carbon, the resulting steel was selected in different grades to form the core and edge of the sword. The characteristic curve and artistic detail was created by a single immersion in water when the metal achieved the correct temperature. Today, samurai swords are considered artistic treasu