Traditional water stones need to be soaked in water prior to use. Normally about ten minutes, or until bubbles no longer escape from the stone. If you've ever used sandpaper, you know that the paper becomes smoother with use. A Traditional Japanese water stone is designed to wear as you use it, thus exposing fresh particulate and producing a very consistent grind all the way down. A slurry or mud will form on the stone which aids in the sharpening and polishing process. This should be left on the stone while sharpening.