This is a beautiful bluish Suita (Aomi Suita) from Mizukihara, Kyoto, cut in the traditional San-gata size. The sharpening surface has a pale bluish-gray to creamy white base, crossed by fine yellow-brown and reddish lines that create a highly distinctive natural pattern.

Mizukihara is one of the well-known whetstone-producing areas of Kyoto’s Nishimono (Western Mine) region, belonging to a different geological area from the Higashimono quarries centered around Umegahata. Mizukihara stones are appreciated for combining the refinement expected of a Kyoto finishing stone with a pleasant degree of feedback and cutting action, making them particularly interesting for Japanese kitchen knives and other fine edged tools.

We rate this particular stone at approximately Hardness Lv. 4.0−. Although it is not an extremely hard stone, it does not feel overly soft or muddy. Instead, it has a firm, tight and controlled sharpening feel, allowing good feedback from the blade without the edge feeling as though it is sinking into the surface.

One of the most distinctive characteristics of this stone is the dark, almost black slurry that develops during sharpening. As the stone releases fine abrasive particles and the slurry incorporates metal removed from the blade, it quickly darkens, creating a striking contrast against the pale bluish surface. The stone is not so hard that slurry is difficult to develop; rather, it offers a good balance between direct sharpening action and the smoother polishing effect produced by the slurry.

The resulting finish tends toward a refined, natural Kasumi rather than a highly reflective mirror polish. On traditional Japanese knives, it can finely refine the soft iron cladding while giving the harder steel core a tighter, brighter appearance, producing an attractive and natural contrast between jigane and hagane.

With its moderate firmness, this stone offers more than simply a soft, slurry-driven Kasumi finish. You can first work directly on the stone with good tactile feedback to refine the bevel and edge, then make use of the developing slurry to soften and unify the final appearance.

Its subtle bluish coloration, beautiful natural lines, firm sharpening feel, and characteristic dark slurry give this stone both strong practical qualities and the individuality sought after in Japanese natural whetstones.

A particularly attractive Mizukihara Suita from Kyoto’s Nishimono region, recommended for Kasumi finishing and final sharpening of traditional Japanese kitchen knives.