Artificial Kaisei stone. The third stone of the groundwork used before Chu-nagura-do. By this stage the marks left by Binsui-do are removed and the surface of the sword will get smoother and finer. The hardness is similar to natural Kaisei. This stone is used by many professional polishers. Dimensions : 20 x 5 x 6 cm, weight 1.7 kg.