Judging from the way the color changes from browns to blues, I would say that poor thing had a bigger blade, and somebody attempted to (as you guys call it) breadknife it, and overheated it. Firefighter, if it doesnt hone up for you, I have an ABS Master in my backyard, who I can ask to experiment with rehardening and tempering (you would need a master to not warp the thin blade) If you try to do it with a torch, the heat will be uneven and wave it out for sure!