This is a hard-type Ozaki Asagi "Gokujō" natural whetstone, suitable for everything from regular kitchen knife sharpening to the pre-finishing stages of straight razors.

In the world of Japanese natural whetstones, the designation "Gokujō" (極上) is not a geological layer name or mineralogical classification. Rather, it is a traditional quality grade assigned by stone dealers, wholesalers, and quarry operators. Historically, stones were often ranked in categories such as Nami (Standard), Jō (Superior), Tokujō (Special Superior), Gokujō (Premium), and Daigokujō (Highest Premium). Within this hierarchy, Gokujō signifies a particularly high-grade stone selected for its superior overall quality and performance.

Ozaki has long been regarded as one of Kyoto's respected natural whetstone-producing areas, particularly among razor users and craftsmen. Hard, finely structured examples are especially valued for their ability to produce keen, refined edges with exceptional clarity and precision.

This stone comes from the long-held collection of a Japanese natural whetstone enthusiast. Having been preserved for many years, it retains the distinctive atmosphere and character of older Kyoto natural stones that are becoming increasingly difficult to find on today's market.

The stone exhibits an exceptionally dense and uniform structure throughout, combined with the calm and elegant coloration characteristic of fine Asagi stones. Although relatively hard, it offers a smooth and highly controllable sharpening feel while generating an extremely fine and delicate dark slurry during use.

It is particularly well suited as a pre-finisher for straight razors, helping to refine the edge before the final finishing stage. It also performs beautifully on kitchen knives and smaller edged tools, producing an elegant kasumi finish with attractive contrast between the hagane and jigane.

This stone possesses the distinctive "quiet fineness" and refined sharpening feel often associated with older Kyoto natural whetstones. As a result, it is appealing not only as a practical sharpening tool but also as a highly collectible piece that reflects the history and tradition of Kyoto's natural whetstone culture.