This is a natural medium-grit whetstone said by its previous owner to originate from Awashima, Wakayama Prefecture.

In Wakayama, the name “Awashima,” also written with the characters 淡嶋, generally refers to the area associated with Awashima Shrine in Kada, Wakayama City, and the nearby Tomogashima Islands. According to the shrine’s tradition, its deities were originally enshrined on Tomogashima before being transferred to Kada on the opposite shore.

However, “Awashima-to” is not a historically established or systematically classified whetstone designation comparable to Kyoto finishing stones or Amakusa stones. It is more appropriately understood as a regional name applied to natural stone said to have been collected around the Awashima and Kada area and found suitable for sharpening. Since neither the exact collection site nor records of commercial whetstone quarrying in the area have been confirmed, the stated provenance should be regarded as information passed down by the previous owner.

The hardness is rated at a strong Lv. 4.5 out of 5. Its sharpening surface is considerably harder than that of a typical natural medium-grit stone and resists dishing during use, allowing precise sharpening while maintaining the flatness of the blade.

During test sharpening, the stone did not naturally produce a large amount of slurry. Instead, it gave the impression that the abrasive particles held firmly within its hard, tightly compacted surface were working directly against the blade. Its sharpening action therefore appears to rely more on fixed abrasive particles than on loose slurry. Rather than softly clouding the soft iron, it tends to refine the existing scratches and produce a bright, crisp, and well-defined luster.

Its character differs from that of softer medium-grit stones that release abundant slurry and create a gentle kasumi finish. This stone excels at refining the cutting edge and keeping the sharpening surface crisp and precise. It is particularly well suited to woodworking tools requiring a high degree of surface flatness, including planes, chisels, kiridashi knives, utility knives, and carving tools.

For traditional Japanese knives such as deba, yanagiba, and usuba, it can be used to adjust the steel cutting edge and refine scratches left by a coarser medium-grit stone. It can also be used on high-hardness kitchen knives to refine the edge geometry after the coarse-sharpening stage and prepare the blade for the next finishing step. This makes it an interesting option as an intermediate finishing stone or pre-finisher before progressing to a finer Japanese natural finishing stone.

However, this is not a particularly fast-cutting stone. It is therefore unsuitable for repairing major chips, making substantial changes to the edge geometry, or quickly removing deep scratches left by a coarse stone. Its characteristics are best utilized after the initial foundation has been properly established with a coarse stone or a more aggressive synthetic medium-grit stone, followed by precise refinement of the edge and sharpening surface.

Because the stone produces relatively little slurry on its own, a diamond plate or Nagura stone may be used when necessary. Raising slurry in advance improves the stone’s initial response and creates a gentler feel against the blade. This method may also help reduce the brightness of the finish on the soft iron.

On the other hand, this stone may not be ideal for knives with uneven bevels, soft stainless cladding, or applications requiring a uniform, soft kasumi finish created with abundant slurry. A very hard stone selectively contacts the higher areas of the blade; if the bevel has not been sufficiently flattened, some areas may become noticeably brighter and produce a patchy appearance.

When finishing a wide bevel evenly, we recommend first flattening and preparing the bevel thoroughly, raising a slurry, and sharpening with light pressure.

Bearing the name “Awashima,” an area closely associated with Awashima Shrine in Kada and the nearby Tomogashima Islands, this is an exceptionally hard natural medium-grit whetstone. It offers excellent surface retention and a distinctive sharpening character that produces a bright, well-defined finish on soft iron. Recommended for users who prioritize precise edge formation and flat-surface sharpening over the soft, slurry-rich action of a more yielding medium-grit stone.