The Habitat KNASA Chef Knife edge is formed from an ultra hard metal alloy permanently bonded to a body of high quality stainless steel. The edge material has Rockwell (HRC) hardness in excess of 70. The maximum Rockwell hardness for steel is in the range of 64-65. Steel gets increasingly brittle as the HRC increases. This is not the case with KNASA. The ultra hardness and ductility of the KNASA edge are the reasons for dramatically extended edge life.
Proper care and maintenance of a steel knife involves hand washing and drying, using knife friendly cutting surfaces, and storing in a safe place to protect the edge. We recommend all of these steps as well. Using a honing edge to align the edge of a steel knife will briefly bring back the fine sharp edge. You have to hone a steel knife because steel is relatively soft, folds over, and must be re-aligned. The KNASA is so hard and strong it does not fold over. WE DO NOT RECOMMEND using a honing edge on the KNASA Knife.
When you feel the knife is not as sharp as you would like, we recommend one of the following:
1) Send it to Habitat for complimentary lifetime sharpening - which involves a small service charge to cover return shipping.
2) Sharpen it by hand on ceramic or diamond "whetstones".
3) Use a ceramic specific home electric sharpener such as the Chef's Choice Model 700. These use diamond sharpening media which is necessary to cut the KNASA edge. We recommend a very light touch (i.e. don't grind off a lot of material).
Our testing shows dramatically extended sharpening intervals, which will, of course, vary from user to user depending on factors specific to your use and the quality and type of your steel knives.