I recall reading something where he explained why he did not use a newer super steel, and he said that he was extremely familiar with the steel that he uses. He said he didn’t see any advantages in using a newer steel and some disadvantages. His knives are at a fairly low Rockwell so that they are easy to sharpen and also not break in use. If he used a newer steel, he would still heat to the same Rockwell rating so no point to using a more expensive steel. He doesn’t want his knives to be super hard.