Sheet bend
The sheet bend is a bend knot. It is practical for joining lines of different diameter or rigidity. It is quick and easy to tie, and is considered so essential it is the first knot given in the Ashley Book of Knots. Additionally, it is one of the six knots given in the International Guild of Knot Tyers’ Six Knot Challenge, along with the clove hitch, bowline, reef knot, round turn and two half-hitches, and sheepshank.