Contour or gape darts will help you fit the contours of the upper body more closely than a regular block/sloper because we eliminate most of the ease. If you do not make these adjustments you will, as you cut into the neckline, have gaping. When we cut away a portion of the neckline the garment loses the support of the shoulder and it will fall into the hollow area over the bust. These darts help to avoid fitting problems before they are incorporated into the design.