I was first shown this braid by a Greek lady on a bus in the Czech republic. Later a friend who’d grown up on one of the Scottish islands told me that she’d made the same one as a child. It was a useful and easy to make cord but it didn’t have a name. Discussion on the Braids and Bands email list has revealed that it’s found in several countries, often without a name although several were suggested including finger knitting, monk's cording, and idiot’s cord.
Method 1 below is the one I was shown by the Greek lady. It also appears in a Dryad leaflet, Cord Knotting, where it is called finger knitting. The loop is alternately on the right and left index fingers. The second method comes from Beyond Weaving by Candace Crockett where it's called finger knotting with one loop — the loop is always on the left index finger.
The two methods give different structures — the second one is triangular, the other more rounded. This shows up well when the braids are worked with two colours. Both methods start with a slip knot on one of the strands. I find I can get a better rhythm going when using the first method.
1. The loop is on the right index finger — take the left index finger through the loop in the direction of the arrow and pull back a loop of 2. Drop the loop off the right index finger and pull tight.
2. The loop is now on the left index finger — take the right index finger through the loop in the direction of the arrow and pull back a loop of 1. Drop the loop off the left index finger and pull tight.
1. Take 2 under 1 and push a loop of 2 through the loop on left index finger.
2. Drop the loop of 1 and pick up the loop of 2 on the same finger (left index). Pull tight — you will probably need to pull on both strands.