Uses: The Blood Knot is used to join two lines of similar size, e.g., when joining sections of leader or tippet.
Tying it: There are several methods of tying it. The animation above shows each half being created separately, which provides a good picture of the structure.
An alternative method is to just overlap the two ends and twist them together for about ten turns. Then go to the center of the twists and create a hole. Pass the two ends the opposite way throught the hole. Whichever method is used, the knot should be symmetrical about the middle with the twists continuing in the same direction.
Advantages: The Blood knot is a simple, easily learned and very effective way of joining two similar sized lines.