For many years, knife manufacturers have been trying to use increasingly harder steel to achieve the ultimate cutting adge. The hardness of stainless steel is measured on the Rockwell Scale, with 62° being the highest grade commercially available. However, the brittleness of such hard steel has always been a limiting factor.I.O. Shen has overcome this problem by using an inner core of super hard Rockwell 62° steel protected by two layers of softer, shock absorbing Rockwell 10° stainless steel on the outside to produce the ultimate cutting edge. I.O. Shen call this Triplex Steel Technology.All of the knives in the I.O. Shen Mastergrade range use the very latest technology to construct blades which are not only amazingly sharp but which will also retain their edge for a phenomenal amount of time. I.O. Shen knives are hand sharpened to a 15° angle, which allows for wonderful slicing and portion control.The unique handle design distinguishes I.O. Shen Mastergrade knives from all others. It is an essential factor in achieving balance and stability. The Tai Tang is not simply an embellishment, it is an integral part of the handle.The handles of I.O. Shen knives are produced from a synthetic material called ebonite which is both durable and heat resistant, although dishwasher cleaning is not recommended.