ZDP189 High Performance Knife Steel from Japan
ZDP-189 is the hardest powder metallurgy stainless steel currently available. Besides HAP40, there is currently no other steel used for knives with comparable properties. The carbon content of 3% makes the steel extremely hard and at the same time the chromium content of 20% counteracts strong rust formation of the steel.
The ZDP steel thus combines the properties of classic Japanese knife steels such as Shirogami and Aogami in terms of blade hardness with stainless steel grades such as VG10 or AUS10. The steel therefore has a very high rust inertia, which makes the steel easy to maintain, but at the same time the steel is exceptionally edge-holding with a blade hardness of up to 67 HRC Rockwell.
However, sharpening this steel requires experience as it is not as easy to sharpen compared to HAP40. The initial cost of a ZDP knife is also comparatively high, as the steel is more expensive and can also be forged less quickly than other Japanese steel types. In return, however, you get an exceptional material that, with the exception of HAP40, cannot be compared to any other Japanese knife steel grade.