The NSK KOGYO Diamond Nagura #400 is a diamond nagura designed to quickly create an abrasive slurry on NSK KOGYO stones from the Hakuto and Oboro series. This slurry, often called todoro, aids in the sharpening process by helping to remove metal particles that accumulate on the stone’s surface as it is used.
It is easy to use: moisten the stone, then rub the nagura across its surface a few times. An abrasive slurry gradually forms, helping to maintain an active working surface during sharpening. The #400 version is recommended for use with the Hakuto #400 and Oboro Knife #400 stones. Its compact dimensions, approximately 41 × 18 × 15 mm, make it easy to handle and allow you to control the amount of slurry produced.
In practice, this nagura primarily offers a convenient way to manage stone clogging during sharpening. It allows you to continue working with the slurry generated rather than simply cleaning the surface. It is therefore particularly useful when regularly using compatible NSK KOGYO diamond stones. However, it is not a universal accessory intended for all stones: its use is specifically recommended with the corresponding Hakuto and Oboro series.
This Diamond Nagura should also be distinguished from the small diamond plate that comes with certain NSK KOGYO stones. The latter is primarily used to refresh or clean the stone’s surface, and the slurry it produces must be rinsed off, whereas the Nagura #400 is designed to produce a slurry intended for use during sharpening. After use, rinse the nagura with water and let it dry completely before storing it.
