Perhaps someone here can suggest a reason for a problem I have with two Ohishi waterstones. I am careful to follow seller's guidelines for use of sharpening media. I have 6000 and 10000 grit stones that have minimal wear on them. They have been stored dry in plastic boxes. I splash them with water before use, although the stones' surface almost immediately becomes "dry". I notice that they gouge very easily during chisel sharpening; and quickly go out of flat, particularly the 10000 stone. I suspect that the (clay?) binder that holds the abrasive particles has degraded to a point that the stones are essentially useless. I have other water stones and oil stones that perform perfectly well, and a new Shapton glass stone that is amazing in performance.