How to Polish a Japanese Sword

Unsheathe the sword from its scabbard, taking care to avoid scraping the sword edge. Detach the blade of the sword from its hilt.

Examine the blade to determine its level of scratch or rust damage, geometry and other fine details of the blade. This will determine which stones or sets of stones will be used for the foundation polishing stage. More warped or damaged blades may require the use of tougher, coarser stone, while minor scratches and dents can typically be polished out with stone of higher fineness or small particle count.

For foundation polishing, set the stone firmly so that it won't move while you're polishing the sword blade. Grind the blade against the stone by pushing the blade into the stone in a consistent rhythm. Apply the requisite amount of force to rub out flaws while trying to minimize the amount of blade material that you end up removing. Wash away residue with clean water while you work.

Once you have removed the flaws to your satisfaction, take the finishing stone and place it on your thumb. Grasp the blade firmly and rub the stone evenly along the length of the blade, along with "tojiru" polishing paste, which is formed from the dust residue of rubbing two foundation polishing stones together. Be very delicate with the blade and avoid scratching the edge.

Apply the "Nugui" powder to the temper line of the blade with a clean cloth or rice paper in order to bring out the details of the blade, making them shine more prominently. Alternatively, you can use a "Hadori" stone on the temper line to achieve the same effect. In both cases, do not apply the finishing material too heavily.

Apply Kurobara or Choji oil to the blade after polishing it to preserve it and help it maintain its luster. Wipe off any excess oil with rice paper or a clean cloth.

Reassemble the blade carefully and either display it unsheathed or return it to its scabbard.