Japanese ink, also known as sumi, is a traditional ink made from soot and animal glue. It has been used for centuries in Japanese calligraphy and painting, prized for its rich black color and smooth application. The ink is typically ground on a stone slab with a small amount of water to achieve the desired consistency. Sumi is often sold in solid form as ink sticks, which artists and calligraphers prepare before use. This ink is not only valued for its aesthetic qualities but also for its cultural significance, playing a vital role in Japanese art and literature.