This is ‘Speed III‘ by Jung Shan, who, as far as I understand, draws digitally and then adds actual ink brush strokes :
I sketched the samurai on a Moleskin watercolor book (21×13 cm):
I used a Pentel brushpen for the black strokes and cold grey Faber-Castell brushpens for the rest:
Then I erased the pencil marks, cut diagonally one of my cheap brushes, prepared a lamp black wash, took a deep breath and stroke:
