Please check the photos. This is a natural Igarashi-to whetstone originating from Niigata Prefecture, located along the Sea of Japan coast.

Igarashi-to is a traditional Japanese natural medium-grit whetstone quarried from geological layers of tuff. Historically, these stones have been used for sharpening kitchen knives, various edged tools, and woodworking implements. They are generally classified as medium-grit whetstones with an estimated grit equivalent of approximately #2000, offering a well-balanced combination of abrasive performance and comfortable sharpening characteristics.

This particular specimen was acquired from a Japanese natural whetstone collector and displays somewhat different structural and sharpening characteristics compared with the Igarashi stones we have handled in the past.

During test sharpening, the stone exhibited a particularly dense, compact, and well-consolidated structure. Its water absorption was also noticeably slower than that of other Igarashi stones we have previously handled, suggesting that this specimen may have a relatively higher-density stone structure.

During sharpening, a fine slurry with an estimated abrasive equivalent of #2000 or finer, possibly approaching #3000, gradually develops on the sharpening surface. Unlike typical Igarashi stones that may produce abundant slurry almost immediately, this specimen generates its slurry progressively as sharpening continues, eventually forming a fine, uniform abrasive suspension.

Because this stone absorbs water relatively slowly, allowing it to soak in water for a short period before sharpening may help accelerate slurry formation and improve abrasive performance from the beginning of the sharpening process. However, this is currently an assumption based on the stone's observed structure and water absorption characteristics, as extended soaking tests have not yet been conducted. We recommend starting with a brief soaking period and adjusting the soaking time while observing changes in slurry production and sharpening feedback.

These characteristics allow the stone to maintain excellent cutting ability while producing relatively fine sharpening scratches, making it particularly effective for refining the marks left by coarser whetstones and preparing the cutting edge for subsequent finishing stages.

Its compact and well-consolidated structure also provides stable blade contact during sharpening. The stone offers a smooth, comfortable sharpening sensation with minimal excessive grittiness or irregular resistance. This balance between abrasive efficiency and sharpening stability is one of the most appealing characteristics of this particular specimen.

What makes this stone especially noteworthy is its ability to retain the effective cutting performance expected from a traditional Igarashi medium-grit whetstone while offering a finer abrasive feel and a denser stone structure than typical examples.

As a result, it can serve not only as a conventional medium-grit whetstone but also as a pre-finisher, helping refine the cutting edge before progressing to finer natural finishing stones. This versatility can contribute to a more efficient and controlled sharpening progression.

This stone is well suited for Japanese and Western kitchen knives, as well as woodworking tools such as Japanese planes (Kanna), chisels (Nomi), and various other edged tools. It is particularly recommended for users who value not only abrasive performance but also smooth blade contact, consistent sharpening feedback, and relatively fine scratch patterns.

A denser and more compact structure than typical Igarashi stones, gradual production of fine slurry, and excellent abrasive performance — these characteristics make this specimen a highly practical and distinctive Japanese natural medium-grit whetstone.

For those who appreciate the individual characteristics of Japanese natural whetstones and seek a smooth transition from medium-grit sharpening to finer finishing stages, this stone is certainly worth considering.