The Sora Combination Honing Steel has two surfaces: a smooth one for everyday honing, and a micro-ribbed one for weekly honing. It has a built-in angle on the handle, which makes it easy to hone your knives to the correct 16deg Shun angle. The Sora Combination Honing Steel is used to hone your knives, that is, to gently realign the cutting edge of your Shun cutlery. With each use of your knife, the edge naturally bends over just a tiny bit. The edge is still sharp, but the sharpest part isn't making contact with the food. The answer is honing. It realigns the edge and prolongs the sharpness.