/ic/ - Artwork/Critique

How is this sort of shading called and how do I learn it? Heavy blocky shadows, almost exclusively pure black, seen it mostly from comic artists.

Could've sworn it's called block shadows, but all I get is digital tools guides so probably misrembering.
High contrast gets me only shitty threshold'ed portraits (allmight in picrel is also like that, but he is better in the manga).
Chiaroscuro uses different values for shading.