I was told, when young, that a sharp blade was usually less dangerous in use than a blunt one. Higher, and potentially less controllable, force needs to be exerted if the blade is insufficiently ‘edgy’ -ie if the front edge is less tapered than it should be.
Many materials (eg crystalline ones), will have properties such that the cut faces spring apart from each other, and the blade surface, thus contributing no ongoing resistance to the passage of the blade. For other substances (eg viscous, rubbery or gelatinous types) the blade movement is further impeded by continuing contact with the just-cut surfaces.
To minimise the total resistance in these cases requires not just a sharp front edge, but minimal surface area of contact between blade and material.
Today’s invention is therefore a low resistance blade which is as slim as a razor blade but which is braced, by a rear-edge ‘spine’, in the direction of blade movement, to allow a comfortable level of cutting pressure.