Japanese sword polishing

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.

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.

Shitaji togi sets the geometry of the blade and encompasses all main stages; utilizing large waterstones of increasingly finer grit.

From this point on, a polisher works to form and grind surfaces and geometry as needed; note that these stages are also where damage is repaired through careful reshaping.

Artificial waterstones are nowadays used for the foundation polishing stage, but almost never used for finishing, as they will produce inferior results compared to natural stones.

The finishing process brings out and enhances all details of a blade so that they are readily visible for observation and analysis, which entails results that must be free of any visual imperfections.

The nugui mixture is applied to the whole blade and if properly done, the hamon will whiten slightly but surrounding areas will darken considerably.

Polishing is a crucial step in preparing a blade for analysis, since it brings out and enhances all external details as mentioned earlier.

This is important because details such as the shape, geometry, particular proportions, appearance of the hamon and grain pattern and so on, are distinctive enough that they can be used to accurately determine the heritage and origin of a blade.