This blue steel chisel was top rated by Fine Woodworking Magazine, calling it "well balanced and a pleasure to use." Aogami Hagane means "blue steel" and is a more complex steel than Shirogami Hagane or "white steel". Edge tools made from "blue steel" give the most durable edge possible, particularly in hard, abrasive woods such as teak and exotic hardwoods. For over 200 years the Matsumura family has had the reputation for supplying only the best quality chisels. Each Blue Steel Bench Chisel is forge-welded by hand from a combination of special Hitachi "blue steel" and wrought iron. After curing in charcoal for several days, they are then individually tempered to Rockwell c64. Complete instructions for care and sharpening are included. Overall length is 9" and blade length is 2¬".

The picture is of an array of different sizes, it is NOT a set.  They are sold by the size and by eaches.