Naniwa

Naniwa Abrasive Mfg. Co., Ltd. is a renowned Japanese manufacturer of sharpening stones founded in 1941, with over 80 years of experience in the abrasive materials industry. The company has gained a leading position through many years of perfecting production processes and using the latest technologies, earning recognition among both amateurs and professionals who sharpen their own knives.

History and Production Philosophy

Naniwa was founded with the vision of creating stones that would be the best at “removing steel,” producing them with the use of the latest technologies. For decades, the company has consistently pursued this philosophy, which has allowed it to stand out from the competition. In 2009, Naniwa obtained ISO 9001 certification, confirming the high quality of its products and services, and ISO 14001, attesting to its environmental responsibility and commitment to sustainable development.

Although Naniwa is best known for producing sharpening stones, its offer includes a much wider range of abrasive products. The company supplies materials for almost all industrial sectors, including cutting and grinding in construction, diamond and abrasive discs for edge sharpening, as well as abrasive powders used in the production of semiconductors and precision devices.

Technical Characteristics

Naniwa stones are characterized by their exceptional ability to maintain flatness even after prolonged use, which makes the sharpening process more precise and predictable. The company primarily uses aluminum oxide (corundum) as the abrasive material, combining it with various binding systems depending on the intended use of a specific series.

Binding Systems

Naniwa uses various binding technologies adapted to the specifics of each series. Resin bonding is characterized by a good balance between durability and sharpening effectiveness, while magnesium bonding provides greater hardness and sharpening precision. The binding material, produced in-house by Naniwa, softens under the influence of water during grinding, which means the cutting edge of the blade is constantly refreshed by new abrasive grains.

Available Product Series

Naniwa Advanced

A versatile series of sharpening stones intended for both amateurs and semi-professionals. It uses aluminum oxide as the abrasive material and resin bonding, providing a good balance between durability and sharpening effectiveness. The stones are available in two thicknesses (10 mm and 20 mm) and require a short soak before use. With a wide range of grits from #220 to #12,000, they are suitable for both edge repair and blade finishing.

Naniwa Chosera Pro

They use aluminum oxide as the abrasive material and magnesium bonding, which provides hardness and sharpening precision. Thanks to their high performance, they are ideal for kitchen knives, woodworking tools, and precision blades. These stones do not require a long soak before use, offer exceptional smoothness of work, and uniform abrasion.

Naniwa Multi Stone

Double-sided series combining two grits in one stone, such as the popular 1000/3000 combination. The first side (1000) is suitable for regular, basic sharpening, while the second side with a grit of 3000 is intended for finishing and polishing the blade. They are characterized by a rather hard binder compared to other series, which translates into a long lifespan.

Naniwa Super Stone

A series starting from a grit of #220, which allows for quickly repairing even the most neglected knife. Before use, the stone should be soaked in water for about 2 minutes. At the 1000-3000 level, you can achieve a truly practical, working cutting edge.

Compatibility and Application

Naniwa stones work well with a wide range of steels – from non-alloy high-carbon steels typical for Japanese tools, to alloy steels used for the production of European tools. Due to their size and shape, larger blocks are suitable for sharpening any wide chisels, plane irons, kitchen knives, and can work with all typical sharpening guides.

Usage and Maintenance

Most Naniwa stones require a short soak in water before use – typically about 2-10 minutes depending on the series. During sharpening, an active abrasive slurry is formed, which significantly improves the effectiveness of the process. The stones are characterized by stability during use and resistance to uneven wear.

Advantages over the Competition

Naniwa stands out in the market primarily due to its use of the latest production technologies and a consistent commitment to optimizing the “steel removal” process. The company offers an excellent price-to-performance ratio, especially in series designed for people starting their journey with water stone sharpening. ISO certification and over 80 years of experience guarantee stable quality and product reliability for long-term use.