I sharpen mine with a flat DMT diamond hone on the outer side of the edge and a piece of wet and dry around a hazel stick on the inner edge. I then replace the wet and dry with leather and strop both sides of the edge being careful throughout not to put a bevel on the inner face of the blade i.e. keep stick flush with the flat of the blade and do not put a bevel on the edge on the inside of the curve.