My neighbor gave me this knife to practice grinding on. It had 8mm electrical arks in the edge. He was actually using it to dig holes in his garden. I had to take it the edge way down. I used a 1x30 and a 3x21 belt grinders. It's a very redneck set up. He got the knife in Hawaii maybe 10 years ago. I didn't take any pictures before because I thought I was going to wreck it. After cleaning up the edge it's a cutting machine. It destroyed a 35 pound case of tomatoes easily. The patina immediately turned a gray color. Any information on it would be awesome. I don't use Google so I don't have access to Google lens.