I would like a knife that is nice and sharp, stays that way for a long time under proper use and can be re-sharpened easily. That is our expectation of a quality and durable knife. How could I get a durable knife that can live up to my expectation? Is there any measurement? For sure, you can choose a knife that holds the edge well with stable handle material.

Edge Retention

Hardness and toughness are two main parameters of edge retention. 

Carbon affects the hardness of steel. High carbon steel contains carbon composition between 0.61% and 1.5 % and it combines with elements like manganese will make the steel very hard yet brittle, the higher the carbon composition, the harder and more brittle the knife becomes. Japanese knife gravitates into using high carbon steel because of the incredible sharpness and long-lasting cutting performance it provides.

Hardness determines how long the sharpness can maintain but it has little to do with the sharpness per se. Sharpness can hinge on the thickness and bevel angle. Let’s take a paper cut as an example, we’ve all been there. A piece of paper is thin enough to be sharp and slice a person’s skin, but we couldn’t use paper for meal prep because of its low hardness. Paper will be so dull that you can’t have another cut after one slight cut on the vegetable.

Toughness refers to resistance to chipping, cracking, or breaking from impacts and torsion pressure. Heat treating is an essential process to reduce brittleness and bring out the supreme performance of the steel. If you want your knife to be a chopper and most of your cutting is chopping bone, frozen meat, and squash, I would not recommend you to use high carbon steel because high carbon will sacrifice some toughness. The knife that contains carbon lower than 0.6% (Low carbon steel) has great toughness but it might lose its edge very soon, therefore, you need to resharpen it frequently. Several knives use 3Cr and even 2Cr, which is a hard pass! You should choose 5Cr or 4Cr at least if you prefer lower carbon steel.

Therefore, San Mai is born for exceptional cutting power and incredible durability, which is the best demonstration of ‘use the best resources in the most important areas’

San Mai steel originated in Japan. It means “three parts” in Japanese. The core of the blade, which becomes the edge, is made of harder steel, while the two outer edges beyond that point are made of softer steel.

This method of creating blades combines the best of both worlds. The hard steel at the center of the blade provides a sharp edge that’s perfect for slicing and cutting, while the softer steel surrounding it gives the blade incredible resistance that helps the knife from breaking, which is a common problem with a pure hard steel knife.

No one kind of steel is built for all purposes. The biggest battle is the trade-off between extreme hardness（best edge retention ) and toughness. That is why we have so many varieties of knife steels. 

Besides the type of blade steel, heat treat, and edge geometry, another major factor is the behavior of the user, which has a significant influence on a blade's edge retention.

In terms of durability, stainless steel knives are your perfect choice, because they don't rust or stain easily. Carbon steel knives are known to keep their sharp edges longer than most other knives and make cutting and slicing safer and easier. A sharp knife makes for clean cuts and clean cuts. If you are in pursuit of ultra sharpness without sacrificing durability, San Mai steel will be your best bet. 

Durability has stong connection with solid and stable handles, if you are interested in what type of handle can last longer, check out The ultimate guide to knife handle material - Find the right one!