Cook the chicken breast with bones intact. They protect the meat as it cooks, which helps keep it juicy, and they help the breast retain its shape. If you want to cook with boneless breasts, place the chicken breast skin-side down on a clean cutting board. The bones will face up. Look for the rib bones.
Breasts sold with the bones attached still retain the ribs and part of the breastbone.
Hold the breast by the rib cage, and use the very tip of the knife to make a thin incision between the ribs and the meat of the breast. Use the tip of the knife to make small cuts across the rib cage, between the ribs and the meat, so you gradually separate the meat along the entire length of the rib cage. Follow the contours of the rib cage with the tip of the knife, holding the breast by the ribs. Continue making small cuts until the meat has completely separated from the bone. Save the bones for stock, or discard them.