To Marinate: Place the chicken wings in a large nonporous glass dish or bowl. In a small bowl mix the soy sauce, oyster sauce, sherry, salt and pepper and pour mixture over chicken; turn to coat. Cover dish and refrigerate to marinate for 12 to 24 hours.
Remove chicken from marinade, disposing of any remaining marinade. Mix all-purpose flour with corn flour in a shallow dish or bowl and toss wings in flour mixture until well coated.
Heat oil in a deep skillet or deep fryer and deep fry wings until crispy and cooked through (juices run clear).