sk5: Japanese equivalent to American 1080 high carbon steel. I don't have anything in this steel myself, but my reading indicates it should have superior edge retention, very good toughness, and very little resistance to corrosion.

VG1: Also from Japan and not to be confused with VG10, it should be roughly equivalent to sk5 except with good corrosion resistance.

3v: Extremely tough tool steel, won't hold an edge quite as well as VG1, and very little corrosion resistance.