What is sanmai steel?

Sanmai steel is a type of laminated steel commonly used in traditional Japanese swords and knives. The term "sanmai" means "three layers" in Japanese, and refers to the composition of the steel. The center layer is made of a high carbon steel, while the outer layers are made of low carbon steel. This creates a blade with a hard and sharp edge, while the softer outer layers provide durability and toughness. Sanmai steel is made using a forge welding process where the three layers are heated and hammered together. It is known for its strength, sharpness, and ability to maintain a sharp edge. Today, it is also used in Western style knives and other cutting tools.