Please check the photos. This is a natural Kozaki Aoto whetstone quarried in the Kozaki area of the Tamba region, Kyoto, Japan.

Kozaki has long been known as one of Kyoto's historic natural whetstone-producing regions, yielding a wide range of stones from Aoto to finishing-grade Awasedo. This particular stone is a practical and user-friendly Aoto, ideally suited for medium-finishing to pre-finishing work on kitchen knives, planes, chisels, and other edged tools. It is especially well suited for single-bevel knives, allowing the user to refine the edge while enjoying the smooth and pleasant sharpening feel characteristic of natural stones.

In terms of hardness, this stone falls around Lv. 3.5+ on the commonly used 5-point natural whetstone scale, approaching Lv. 4.0. While it is not an especially hard stone, it possesses a comparatively dense structure for an Aoto. As a result, water absorption is moderate, the sharpening surface remains stable during use, and the stone offers a calm, highly controllable sharpening experience. In addition, swarf releases easily from the surface, helping to prevent loading and maintain comfortable sharpening over extended periods.

During sharpening, the stone produces a fine, creamy slurry while maintaining excellent cutting ability. It efficiently refines the edge without feeling overly aggressive. The stone performs particularly well after a synthetic stone in the #1000 grit range, serving as an excellent bridge between coarse sharpening and finishing stages.

The resulting edge combines a pleasant level of bite with excellent sharpness, making it highly practical for everyday use. It is also well suited for preparing the foundation of a beautiful kasumi finish, naturally enhancing the contrast between the hagane and jigane.

Whether used as a transitional step before a finishing Awasedo or enjoyed for the distinctive edge characteristics that Aoto stones can produce, this stone offers excellent versatility and performance.

Today, quality Kozaki Aoto stones have become increasingly difficult to obtain. This stone is appealing not only as a practical sharpening tool but also as a valuable example of the natural whetstone heritage of Kyoto's Tamba region.

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 sizes are not accurate. This is a lifetime investment for people who live sharpening their tools, do not hesitate to ask me your questions.”

Dimension :67mm×219mm×50mm ( Approx.) 

Weight: 1835g