>>2750118This brush, and many other brushes the chinese use, have a soft edge on one side of the brush. In the case for this brush, the soft edge will be on the edges perpendicular to the direction of the stroke. You'll want to make use of the innate soft-edges of the brushes for painting soft edges, and make sure that you go hard where you need to. It's easy to not get hard edges in certain areas because you're not pushing down hard enough. Also make sure your wacom/pen settings are on firm or harder because they control opacity with the pen and not manually unless they are glazing color.
Also, the spacing on the brush makes it so that flow will also influence the edge quality and quality of painting. So paint with 20-30% flow in the beginning of the painting, and higher flow when you want to paint more opaque/hard edged areas, such as when you're putting finishing touches on a painting..