Thankyou Nathan, that was my point. Hardened pearlite is just a simplistic descriptive term for a pearlite/martensite mix that allows a file to skip, giving those who don't know, the impression that everything went as it should, although the steel is acually in a poor condition as a blade. There may be much truth in what Doug said about the quality of available steel. Last year I had a piece of 01 that had a longitudinal band running the length of the blade, just about midway, that would not harden. I tried three times. The edge below the band was hard, and the spine and point were hard, but the band, about 3/8" wide, and seemingly uniform, never would harden. Oven heated, decarb protected, soaked, and quenched in Parks AAA.