The butterfly leaf is hinged in the middle with hidden Soss hinges so nothing but the beautiful wood (figured black walnut in this case) shows when the leaf is fully deployed. It aligns itself with the two top pieces so all you need do is push the top halves together to lock the leaf in place. When you are ready to put the leaf away, just pull the two top pieces away from the leaf and lift one end of the leaf. It will fold itself and store itself under the table. Slick and very interesting to watch.