Although I find painting and woodturning instantaneous, and that is my primary interest in them, drawing with a pen and wash is a totally different concept. It is very slow (at least when I do it, it is very slow).

It is not a matter of putting down green to show a field; it is necessary to show that field by a series of lines. Likewise, hills, houses, etc are all defined and shown by a series of short/long, thick/thin marks. The lines and marks follow, in a landscape, the shapes of the hills and therefore define the structure of the ground.