The core of every knife is the blade steel. It is responsible for how sharp you get a knife, how long the knife keeps its sharpness, how stable the blade is, how well it resists corrosion and which sharpening products you need for resharpening. Currently, well over 100 different types of steel (alloys) are used to make knife blades. Some differ only in nuances, while others are worlds apart in composition and manufacturing processes.