Blind drawing (i.e., drawing without looking at the paper) works very well for ‘outside’ contours. That is, with practice, one can get very good at rendering skylines, landscape horizons and outlines of people’s faces. However in the case below, I tried drawing a face in three-quarters profile. This means contours inside the outline must be made visible. It is very difficult to reposition the pen point without seeing where it goes.

Three-Quarters Profile
Pen and Ink Sketch
7″x5″ 111# Moleskin Journal