This is a natural finishing stone from the Nakayama Kurumaguchi line. Kurumaguchi is regarded as one of the most highly respected mining entrances within the Nakayama mine and has long been prized for applications requiring delicate and highly refined edge work, such as straight razors, woodworking tools, and honyaki knives. While stones mined from the center of the tunnel are generally considered the highest grade, this particular stone originates from an outer section of the Shikitomae entrance and contains a slight influence from the Aisa layer.

Despite the presence of Aisa characteristics, the stone remains highly dense and exhibits the refined sharpening feel for which Kurumaguchi stones are known. It provides excellent edge engagement and feedback, allowing the user to maintain precise control throughout the sharpening process. Water absorption is moderate, and the stone generates a delicate, easily managed slurry that contributes to the formation of a keen and highly refined edge.

The resulting edge is sharp, crisp, and well-polished, offering an excellent balance between cutting performance and visual appeal. It is particularly well suited for straight razors and high-hardness steels.

Although influenced by the Aisa layer, this stone still delivers the sophisticated sharpening experience that has made Nakayama Kurumaguchi stones so highly regarded among natural whetstone enthusiasts.

Please note that these are not for beginner sharpeners since they're harder to use.These are natural stones meaning that every single one of them are different so my measured size are not accurate. This is a life time investment for people who lives sharpening their  tools, do not hesitate to ask me your questions.”