It reminds me of ATS-34. A Law Enforcement friend of mine used to give me his Buck Odyssey to sharpen. It would take me hours on a fine German stone. I have a Buck Strider Solution in that steel. Tough stuff. 154 CM seems about the same to me.
ATS-34 is the same thing just made in Japan. 154CM in the early days was vacuum melted then for what ever reason they made a change in the process and quality took a nose dive. A big switch was made to ATS-134 because the quality was always there. At some point the process for 154CM was changed again which brought the quality back up. Which is why your seeing it again in high end knives.
