This is a Kasumi product (combined knife) made by forging steel and base metal together, and is water fired. It has a mirror finish and the steel used is Aogami No. 1. With Pak buffalo pattern. Blue steel is harder than white steel, cuts longer, and is less likely to wear out when sharpened. As a result, it is a little difficult to sharpen, so it is suitable for those who are accustomed to sharpening.