Appraising Sumi
Both Beni and Sumi have luster produced by the skin. Like the way it is with Beni, a good Sumi is the type which develops Maruzome. Sumi has to have a good thickness, and it appears more beautiful when shiny. In contrast, hard sumi with rough texture does not appear beautiful. It must be understood that it is not just the blackness that matters with Sumi.
Truly beautiful Sumi are rare. Currently, appropriate evaluation standards and techniques have not been developed. Quite often, show judges are unable to determine the quality of Sumi. As in Beni, good Sumi possesses elasticity. It adheres to the skin strongly and is solid in its black pigment.
Good sumi is deeply kneaded into the skin. If the skin texture is rough like cotton, however, it cannot become good Sumi. The hobbyist must look for the silky quality of skin in the Koi. Skin quality determines the expression of Sumi. If on a silky skin it will have a strong luster. On a poor skin the shine will be lost.
In a Koi show Tsubo-Sumi is often discussed. In the general sense Tsubo-Sumi is known as Sumi on white skin. Keep in mind however, Nishiki Koi is an expression of artistic pattern. Thinking Tsubo-Sumi as Sumi on white skin, is not an accurate understanding of Tsubo-Sumi.
It is an artistic play of Beni, Sumi, and Shiro, and depending on the shape of a Hiban, the position of Sumi can be critical. It has to be in a critical spot (Tsubo) where it creates a good balance, and yet becomes the emphasis in the artistic play of the pattern.