I think it's that beautiful swedish steel that produces such a slippery edge - and just hard enough - yet not so brittle that you can sharpen them to a really acute point that might crumble if the steel where just a bit harder. It's a balancing act and a series of choices - not all of which seem to make sense at first - and as you use the knives you keep coming back to them because, though they may require a little more frequent sharpening than some, they work so well when cutting and feel so right, you want to sharpen them just to feel them at their best. Personally I enjoy sharpening my Shigefusa's because they are easy knives to sharpen and I actually feel they give more feedback and conform to my "intention" more easily than most other knives.They don't fight the stone and wear so smoothly that I always feel relaxed and at peace sharpening a Shingefusa. For me the magic of these knives is that they may not be first place in any single category but the choices made and the priorities chosen are evident in every knife: exceptional finish, balance, blade stiffness and a solid feel, ease of sharpening, a slick edge, harmonious geometry, and fine grained steel hardened just to the point of perfection - at least perfect for this knife.