This Kiritsuke is crafted from K720 (O2 Steel), differentially hardened and tempered to achieve an edge hardness of 60 to 65 ...

This video covers the process of making a knife using minimal tools, with steel sourced from a 3€ Ikea knife. Index of operation and materials: 0:24 Knife came sharp but with a dent in the bevel 0:42 ...