What is san mai steel?

San mai steel is a type of traditional Japanese blade construction that is composed of three layers of metal. The core of the blade is made of high-carbon steel, which is then sandwiched between two layers of lower-carbon steel. The high-carbon steel provides excellent edge retention and sharpness, while the lower-carbon steel improves the blade's toughness and durability.

San mai construction is often used in Japanese swords, such as katana and tanto, as well as kitchen knives and other cutting tools. The layering of different types of steel creates a visually striking pattern known as a "hamon" on the blade, which is highly prized by collectors and enthusiasts.

Overall, san mai steel blades are known for their exceptional sharpness, edge retention, and durability. They are also relatively easy to maintain and sharpen, making them a popular choice among professional chefs, martial artists, and blade enthusiasts.