Holding the head, slice between the arms and eyes.
Cut off the head, just above the eyes, and set aside. Discard the eyes.
Push the beak (mouth) out from between the arms.
Place the knife just inside the white side of the head, being careful not to pierce the ink sac; cut the head open.
Use your thumbs to peel back the head to expose the intestinal sac.
Working from one side, break the intestinal sac away from the inside of the head (try not to break the ink sac); discard. Place the head on a chopping board, skin side down. Grasp the skin on one side and, using your thumb to separate the skin from flesh, peel the flesh away from the skin.
Rinse the head or wipe with a clean, damp cloth. Cut the head and arms into pieces for cooking.