In contrast with the typical Western view of imperfection as being something to overcome and eliminate, much of traditional Japanese art idealizes the concept of "imperfect." The term used to summarize this is Wabi-sabi, an aesthetic that sees beauty in the imperfect and incomplete. It has its roots in the Buddhist worldview that "nothing lasts, nothing is finished, and nothing is perfect." In the art world, the term is often translated into English as "flawed beauty."
I've written before about the Etegami motto which was popularized by artist Koike Kunio. It goes: Heta de ii. Heta ga ii, which translates roughly to "Clumsy is not a problem. In fact, Clumsy is desirable!" I think this is Etegami's way of expressing the wabi-sabi philosophy. The shaky lines, the blankness of the background, the spaces left unpainted even within the outline of the image-- these and other characteristics of traditional etegami go against the grain of an artist who seeks perfection and completeness. An etegami artist has to be willing to give up a certain amount of control and see imperfection as beautiful.
When I make etegami, I have to resist my natural impulse to control the process. One way I give up control is by holding the ink brush by the tip of its long shaft with just two fingers, and moving the brush ever so slowly across the paper to create the outline of the image. I've written about this in my post on "living lines." In the wabi-sabi view, the clumsy jerks and bumps and blotches that result from this method are beautiful.
When I add color to this clumsy outline, I lay the paint brush against the paper and let the weave of the paper control the spreading of the paint. This is why I use washi cards with a high "bleed" factor. If I'm not careful, the paint quickly spreads beyond the border of the image. So I hold back on the paint, allowing plenty of blank margin between it and the border of the image. These blank areas add to the feeling of wabi-sabi incompleteness.
I find that if I forget the wabi-sabi attitude (which happens a lot), I end up with artwork that may be attractive enough on the surface, but lacking in something at a deeper level. It looks too controlled. It becomes difficult to distinguish from other kinds of art. To my eyes, it is no longer etegami.