A hasty or undetailed drawing often made as a preliminary study. Traits include rough lines, monochrome or basic coloring, and left over structural shapes.
Abbreviated on Pixiv as "rkgk", which comes from the Japanese word for sketch (らくがき, 落書き, rakugaki). Not all pictures tagged as "sketch" by the artist should be tagged as sketch on Danbooru. The picture must look like a sketch for it to apply. Translated tags have been removed from this wiki, because artists tend to use this tag in a very misleading way.
Sketches are not sufficient reasons for flagging. See howto:flag.
Not to be confused with sketching, which is used for when a character within the image is sketching an image themselves.
