How do I read the codes on the caps?

Copic has its own color system based on which we assign the names of the markers. The letters represent a rough hue (dominant color family, e.g. R stands for 'red', B for 'blue' and 'E' for earth colors). The first digit expresses the saturation of the color - the closer the digit is to 0, the more transparent it is. On the other hand, digits closer to 9 mean that the color is rather dull or muddy. The final digits represent brightness with 000 being the brightest and 9 being the darkest.