Schiele continued Klimt's passion for female portrait sketching, constantly looking to refine his skills through practice and experimentation. Both would use pencil and chalk on a variety of paper types.
Picasso and Klimt held a similar desire for simplicity when it came to this art form - concentrating purely on constructing form from the most minimalist of lines.
Some sketches would go into much greater detail, particularly study pieces for large scale paintings, but many simpler drawings were done simply for enjoyment.
To see such minimalist drawings is almost like admiring a model without makeup - the raw beauty, untouched and pure. Schiele was able to achieve so much in one's mind, through the suggestion of just a few lines.
Much of the Vienna Secession movement was bold, both in canvas size and also colour. Such work required space and time, whilst simpler drawings could be completed at a whim, with just a small sketchpad and pencil. Passionate artists like this would often get a spurt of inspiration which would need to be satisfied immediately.