This knife is a flagship of the sheath knife of the ROCKSTEAD. The shape of the blade is made from a consecutive convex surface. This technology doesn't permit other follows, and we have confidence in this surface. When you strongly press this knife against the telephone book, it will cut like cutting the butter. Please confirm our HONZUKURI blades that evolved. ZDP189 is a powder stainless steel material developed for cutlery. It is a product of nanotech. However, it is an unsuitable knife to the beating cut. This knife has a narrow tang. Selling starts in 2013.