Naniwa chosera grindstone ss 3000 grain 3000 you have high it is intended for the professional, which places the highest demands on a fine and gentle grinding. Whether coarse grinding, fine grinding or the finest polish, the chosera is the absolute high end product under the water grinding stones: even the hardest steel can be wonderfully sharpened with the naniwa chosera grinding stone. Small toishi for straightening the grinding area.