It is made from vegetable carbon and glue, is molded into a form and fired in a kiln. To paint with this stick, you need to mix it with water by grinding it with water in a circular motion on a slate stone specifically made for this purpose. Besides giving you the painting medium, this process also is a wonderful meditative exercise. By grinding ink, you can clear your mind before you begin painting. Both Japanese and Chinese ink are also available in liquid form.
Liquid ink is an inexpensive way to begin paintng and is easy to carry around for location painting.
There also are some techniques that respond better to liquid ink than stone ground ink. One of the drawbacks to liquid ink, of course, is that it skips the meditative process. Incidentally, India ink is not the same as liquid sumi ink. I began painting sumi-e by accident. An artist from Japan was in residence for a year at my college, and I took the course and fell in love with painting.