The traditional Japanese method of heat treating swords yields a blade with a hard edge and a soft spine.  This method manifests itself in the form of the “hamon,” a visible line in the steel.  This line was traditionally used to ornament the blade.  On this video, three blades are “clay hardened”, leading you from simple heat treating and clay layout techniques, through more complex and challenging designs.  Includes information about various kinds of traditional hamons and how to make them, basic heat treating of carbon steel, and sources of tools and equipment.  1:15 minutes.  $40 + shipping ($5 US or $10 international).