this loop is ‘perfect’ for loop-to-loop line-to-leader or leader-to-leader connections for anything but the biggest of fish. super easy to tie, the loop stays in line with the standing end of the monofilament and not ‘kinked’ to the side as with a Double or Triple Surgeon’s Knot. to be honest, i’m not sure it really makes any difference in leader/fly presentation to the fish but it does because i believe it does. offset kinks look messy !
i really like this video by Jim Thielemann. rarely found on any step-by-steps or diagrams is the trick we find here of passing the line around the thumb to create the second loop. this keeps the whole knot visible with the loops separated as opposed to pinching the ensemble together and then trying to pull the second loop through the first to finalize/tighten the knot. this also makes for a better control of the size of the final loop.