Samurai swords, or katanas, represent some of the most dangerous weapons used throughout history. Featured in movies such as Kill Bill, these swords were used by samurai warriors to rule empires. If you own a samurai sword, you owe it to yourself to keep the sword as sharp and polished as possible. This beautiful weapon remains one of the great symbols of strength in humanity's history. Be sure to use the greatest amount of care possible when sharpening your sword.
Ignore the edge of the sword. People commonly fall into the trap of worrying about the edge of the sword during sharpening. Instead, allow the edge to reveal itself. You should focus on removing metal until the edge becomes naturally exposed.
Set up your workspace in good light. Use the block of wood to prop up your sword. Use the file to roughly shape the edge of your sword. Your hand should move in consistent motions--each one the same as the last. Throughout the process, keep the file at a 30-degree angle. Additionally, make sure to sharpen the sword evenly on both sides. So after 10 strokes on one side, flip your sword over and perform 10 on the other side.
Polish the sword. Apply a thin layer of oil to the surface of the blade. Next, polish the sword in a back and forth motion with the whetstone. You do not want to perform circular motions; this will disfigure your sword. Again, perform your strokes at a 30-degree angle. Make sure you polish the entirety of the sword’s surface. This way, you will have a uniformly polished sword.
Finish the job. Use a small piece of 400-grit sandpaper, about the size of a postage stamp, to sand the blade. Wet the sandpaper with a little bit of water to prepare to wet sand the sword. Wet sanding will minimise airborne dust and debris and lubricate the sword for a finer finish. At a 30-degree angle, run the sandpaper along the edge of the blade. You must be extremely careful during this procedure, as the blade can easily cut you. After you are done, you may want to rub the blade with water and vinegar to brown the blade's surface. This technique makes sharpening less obvious.
Remain careful and patient throughout the procedure. You should eliminate outside distractions, as accidents commonly occur during sharpening. Practice on an inexpensive stainless steel wall hanger first. This way, you will destroy a cheap item rather than your expensive samurai sword.
Avoid sharpening antique swords. You will likely destroy their value by doing so; rather, leave this to the experts. Do not use power tools. These produce too much friction and can ruin the sword’s geometry. In case you do need to use a power tool, use one with slow grinding wheels such as a Makita wet grinder.