Japanese Natural Whetstone Nakayama Kiita Kan Aisa 668g from Kyoto

This is another rare, top-quality old-school Nakayama natural finishing stone.

The surface displays a highly unusual and abstract Kan (環) pattern, interrupted by a natural carbonaceous fossil inclusion. This inclusion is soft, safe, and harmless and does not interfere with the sharpening process.

In JNAT terminology, Kan refers to distinctive natural ring-shaped, curved, or wavy patterns that can sometimes resemble the growth rings of a tree.

This is a natural finishing stone from the legendary Nakayama Kurumaguchi line. Kurumaguchi is regarded as one of the most respected and highly prized historic mine entrances of Nakayama and has long been valued for applications requiring exceptionally delicate and high-quality edge finishing, including straight razors, traditional Japanese woodworking tools, and Honyaki knives.

Sharpening Characteristics

The stone is exceptionally dense and provides the refined sharpening feel for which high-quality Kurumaguchi stones are renowned.

It offers excellent contact with the blade and superb tactile feedback, allowing precise control throughout the sharpening and finishing process.

Water absorption is moderate. During use, the stone develops a fine, gentle, and easily controlled slurry that helps produce an exceptionally sharp and highly refined cutting edge.

The resulting edge is crisp, sharp, and beautifully polished, providing an excellent balance between cutting performance and visual refinement.

This stone is particularly well suited for straight razors and high-hardness carbon steels.

This combination of density, fine abrasive action, excellent feedback, and precise control is exactly what has made Nakayama Kurumaguchi stones so highly prized among collectors and enthusiasts of Japanese natural whetstones.

Kanji and Stamps on the Stone

中山合砥 (Nakayama Awasedo) — Natural finishing stone from Nakayama.

合さ / Aisa — Aisa geological layer.

黄板 (Kiita) — Yellow-colored finishing stone / Kiita.

Special stamp associated with Kyoto natural whetstones:

• 天然 (Tennen) — Natural
• 砥石 (Toishi) — Whetstone / sharpening stone
• 京都 (Kyōto) — Kyoto
• 特産 (Tokusan) — Specialty / traditional local product

Specifications

• Dimensions: Approximately 94 × 199 × 18 mm
• Weight: 668 g
• Estimated Grit: Extremely fine, approximately #10,000+
• Hardness: 4.0+
• Nagura: Not required, although using a Nagura stone will significantly accelerate slurry development and the sharpening process.
• Recommended for: Straight razors, traditional Japanese woodworking tools, premium kitchen knives, and Honyaki blades.

This rare Nakayama Kurumaguchi Aisa Kiita Kan combines historical provenance, distinctive natural aesthetics, and exceptional finishing performance, making it equally attractive as a serious sharpening tool and as a collectible Japanese natural stone.