The Japanese Knife Evangelist 5-7

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From Fire to Ice: Unlocking Durability Through Sub-Zero Treatment

Sub-Zero Processing is an advanced technique that elevates knife-making beyond traditional quenching. While ordinary quenching transforms most of the steel into martensite, it often leaves behind unstable retained austenite. Over time, this can cause warping or weaken the blade.

By cooling the steel below 0°C with liquid nitrogen, Sub-Zero Processing forces nearly all retained austenite to transform into martensite. The result is a blade with unmatched structural stability, greater wear resistance, and long-lasting sharpness.

For chefs, this means more than technical precision—it means a knife that remains true to its form, performs reliably over time, and retains its edge even under the demands of daily use. It is a marriage of tradition and science, where the wisdom of fire meets the precision of ice.

Our Story

  • Tradition of Sakai, in Your Hands

    "Where can I find a truly great knife?"
    We started KIREAJI to answer that question. While the number of skilled craftsmen is declining in Japan, many people overseas are seeking authentic blades. With that in mind, we carefully deliver each knife—bridging tradition and kitchens around the world.
Our Story