Using the same shuttle begin a second ring and tat up to the midpoint.

Next bring the ring thread up through the picot on the first ring.

Pull gently on the ring thread to remove the excess thread. Make sure that the last double stitch formed touches the picot; adjust tension or compression as needed.

Finish tatting the ring and close allowing the new ring to surround the first ring.

The onion ring join makes it possible to create the look of a ring surrounded by a chain but using only one shuttle. If a second shuttle is introduced then regular chain work can be accomplished and additional rings thrown off the chain using the second shuttle.