KOTAI means solid in Japanese, because at the core of KOTAI's values is our promise to demanding chefs to offer them a knife that will be their most reliable partner in the kitchen, for decades.
But KOTAI also means "solid" like the chemical state, which is a reference to what is at the center of KOTAI's quality: the optimal chemical composition and molecular structure of its steel.
The quality of a steel depends on its chemical composition, how much carbon, chromium, molybdenum, vanadium and other elements have been added in its formula.
Carbon increases the blade's capacity to be hardened and therefore take a sharp edge and hold it. Chromium increases the blade's corrosion resistance. Molybdenum and vanadium improve wear resistance and toughness. All these elements must be very carefully balanced; too much or too little of certain elements and the blade may become brittle, prone to chipping and corrosion or unable to hold an edge for more than a few cuts.
The Japanese 440C high-carbon steel used in KOTAI knives achieves the perfect balance of hardness, durability, corrosion resistance and low chance of chipping. With over 50% more carbon content than regular knives, its edge will stay sharp for much longer. Less time sharpening and more time cooking delicious meals.
Key elements in KOTAI’s Japanese 440C steel:
- 0.95% carbon for strength and hardenability. Thanks to its high-tech vacuum heat treatment, KOTAI’s 440C steel is hardened to an optimal HRC 60.
=> The blade has a razor-sharp edge out of the box and retains it, cut after cut.
- 17% chromium to prevent corrosion and improve wear resistance.
=> The blade is rust-resistant and does not scratch easily.
- 0.16% vanadium for finer steel grain
=> The blade can be sharpened more easily than with rougher steels.
- 0.45% molybdenum to increase blade flexibility and toughness.
=> The blade will not chip even under stress.
Chemistry also plays a role again when the steel is tempered to modify its molecular structure. High-end knives are heated and instantly cooled down through vacuum heat treatment that makes the iron molecules rearrange in a much more dense manner, giving the steel a "martensitic" structure.
Properly tempered martensitic steel acquires a high degree of hardness and toughness, both very desirable properties for high-end knives.