Learn how to tie the Alpine Butterfly Loop — a strong, dependable knot for creating a fixed loop in the middle of a rope.

Let’s start with the basics: The running end is the end you manipulate. The standing end is the part you don’t manipulate. The bight is the curve between the running end and the standing end.

It sounds like something you’d stumble upon if you went the wrong way at Hogwarts: oversized tools, giant knots, and rope as far as the eye can see. But for knot expert Des Pawson, it’s just normal ...