Sword polishing is part of Japanese swordsmithing where a blade is polished after forging. It gives the shining appearance and beauty to the sword.
When the rough blade is completed, the swordsmith turns the blade over to a polisher called a togishi, whose job it is to refine the shape of a blade and improve its aesthetic value. The entire process takes considerable time, in some cases easily up to several weeks. Early polishers used three types of stone, whereas a modern polisher generally uses seven. The modern high level of polish was not normally done before around 1600, since greater emphasis was placed on function over form. The polishing process almost always takes longer than even crafting, and a good polish can greatly improve the beauty of a blade, while a bad one can ruin the best of blades. More importantly, inexperienced polishers can permanently ruin a blade by badly disrupting its geometry or wearing down too much steel, both of which effectively destroy the sword's monetary, historic, artistic, and functional value.
On high quality blades, only the back of the blade and the adjacent sides, (called the shinogi-ji), are polished to a mirror-like surface. To bring out the grain and hamon, the center portion of the blade, (called the hira), and the edge, (the ha), are usually given a matte finish. Microscopic scratches in the surface vary, depending on hardness. Smaller but more numerous scratches in the harder areas reflect light differently than the deeper, longer scratches in the softer areas. The harder metal appears more matte than the softer, and the manner in which it scatters light is less affected by the direction of the lighting.
Sharpening and Cleaning Edit
In the Sengoku Period of Japan, samurai warriors would normally pick up animal droppings, or gravel, fold it inside some paper or animal skin, and scratch the blade to clean the blood off his sword. They would still be polished occasionally, if needed. The shinobi would also learn these techniques according to the Akutagawa Kaden. The Shoka no Hyojo manual from the 17th century gives examples of less professional approaches to sharpening and cleaning a blade.
Hayanetaba no Koto (Fast Sharpening) Edit
Skin a toad in the hour of the Cockerel (sunset) on the fifteenth day of the eighth month and dry it in the shade. Carry this with you and when you wipe your sword with it, the sword will have the ability to cut through iron and stone. (Netaba no Daiji oral tradition).
Nori wo Otosu Kusuri no Koto (Blood Removal) Edit
Skin a mole and dry the skin in the shade, sprinkle powdered boseki stone on the fur side and carry this to wipe the blood off your blade after you killed someone.