Repairing a broken natural Japanese waterstone using urushi lacquer. Natural urushi lacquer is strong enough to repair the stone but will not interfere with sharpening and polishing as some glues may. Carving a cypress base to hold the stone together as well as using urushi lacquer to reattach the halves provides a double solution. The stone is a Kumamoto binsui-do, approximately #700, from Monotaro in Japan. Urushi is from Watanabe~san.