Sumi-e or Suiboku-ga (ink wash painting) is a Japanese or Chinese way of drawing a picture. We use only black ink, which is called 'sumi', using a thin brush (fude). Of course, we don't use any colors except black. We usually draw on paper or silk cloth.
In Sumi-e, we usually grind inkstick over an inkstone to obtain black ink, but prepared inks (bokuju) are also available. Most inksticks are made of either pine or oil soot combined with animal glue.
Even if you want to put some colors, they should be one or two thin ones.
This may be new to you, but I hope you'll try it once, because you have already mastered anything Japanese, like Ukiyo-e and Haiku (very short poem) , not speaking of Judo, Kendo, Karate, or Sumo.