This Koma-Nagura was acquired from a collector who specializes in Japanese swords. As the bottom surface of the stone is not perfectly flat, there are traces of adhesive on the base from when it was previously mounted on a wooden stand. A wooden base is included with this item. When mounting the stone, the buyer is asked to adjust the thickness of the adhesive as needed to ensure stable and secure use. Please understand the condition as that of a tool that has been used in actual practice, and make use of it as a practical Koma-Nagura for Japanese sword polishing. There is a light dent on the sharpening face as photo shows.

Mikawa Koma-Nagura (For Sword Polishing)

Mikawa Koma-Nagura is, as widely known, a natural nagura whetstone quarried in the Mikawa region of Aichi Prefecture. Among Mikawa nagura stones, it is characterized by an especially fine particle size combined with high cutting efficiency, and has long been used in Japanese sword polishing.
In the field of sword polishing, it is employed after the Chū-Nagura stage and plays a crucial role in further refining the precision of the blade surface. The Mikawa nagura stones distributed under the Asano name have been carefully classified into approximately eight distinct layers, ranging from Mushi to Koma, thanks to the efforts of Sakamoto-san. In practical sword-polishing work, however, these stones are generally treated as two functional categories based on use: Chū-Nagura and Koma-Nagura. This stone corresponds to the characteristics of the Koma-Nagura category. This piece was acquired from a collector who specializes in Japanese swords. While it is not possible to definitively identify the exact layer, test sharpening suggests that it possesses the very fine-grained properties corresponding to the Koma layer in the Asano nagura classification. During use, it produces a fine black slurry in a controlled and gentle manner, allowing the blade surface to be refined evenly without excessive material removal. It is a highly practical Koma-Nagura for sword polishing, offering excellent precision and control when transitioning from the Chū-Nagura stage toward the final finishing stones. Please note that these are not for beginner sharpeners since they're harder to use.These are natural stones meaning that every single one of them are different so my measured size are not accurate. This is a life time investment for people who lives sharpening their knives and tools, do not hesitate to ask me your questions.