The Keyline is a contour line, the one that goes through the Keypoint of the valley. A true keyline only exists as a feature of a Primary valley. Keyline pattern is started by taking a contour around a ridge and plowing up from this line. The breakthough of this pattern cultivation is that as you plow uphill from this contour, the lines begine to slope slightly downhill towards the ridge, which control the water to move away from the valley. In valley shapes one finds a contour and plows down, which has the opposite effect of plowing on the ridge shape. Valley's are the minority landform in the landscape. Most of what you are working with is ridge shapes.