This video shows how to work a needle join on single crochet (UK – double crochet), half-double crochet (UK – half treble), and the moss stitch.
Below is a photo tutorial that demonstrates how to join a double crochet circle (UK – treble crochet) with a needle join.
The above photo tutorial on the Needle Join (NJ), also known as the invisible join. The background music in the video is performed by Bonnie Hodge with Lady and a Harp. You can visit her YouTube channel here: https://www.youtube.com/user/ladyandaharp.