Just did this at a local artists gathering. It is a quick sketch done with a modern sumi brush (self-inking kind). Really love the look of the strokes! It is something that Painter can't really reproduce. So I am officially using this sumi brush for doodling.
Lineart: Done with self-inking sumi brush. 1/2 hr. Colour: Painter 9. 1/2 hr. No ref