Above is an example of a Sumi grinding stone. This inkstone is an ornate one and very beautiful. This ink slab was carved in a 'cucurbit' shape. This shape stands for good fortune and every success. This is the stone that I use.
The Sumi stone for grinding the ink is an important tool in the creation of Sumi-e. An inkstone is literally a stone mortar for the grinding and containment of ink. Traditional Chinese ink was usually solidified into sticks for easier transport and preservation. Even a small amount of water could be applied to the end of a stick of ink, and that end would be ground with the flat surface of the ink stone. A larger quantity of ink could be ground from a small pool of water placed on the inkstone. Water could be stored in a water-holding cavity on the inkstone itself.
The inkstone, together with the ink brush, inkstick and paper, are the four writing implements traditionally known as the Four Treasures of the Study.
Each artist prepares his/her ink in their own special way creating a calm and empty mind. I generally use a black Shanghai Premium stick. I moisten the slab and use a circular motion to grind. I like my ink to have a dark and smooth consistency. The contemporary sumi-e you see here by Casey Shannon is called Winter. This image is an example of the various shades you can create by adding water to your ink. Variation in color of ink adds depth to your painting.