Knots
The blood knot: the tidy join
Draft reference — pending review.
What it's for
The slim, symmetrical join for two lines of similar thickness — five to seven turns each side, tags tucked back through the middle in opposite directions, tightened into a neat barrel. Smoother through the rings than a surgeon's knot, but fussier to tie: a bench knot more than a boat knot.
The steps
Overlap
Cross the two ends over each other with a generous overlap — you need working length on both tags.
Wrap one side
Wind one tag five to seven turns around the other standing line, then bring it back and drop it through the gap where the two lines cross.
Wrap the other
Repeat with the second tag around the first standing line — same turns, and tuck it through the same central gap from the opposite direction.
Wet and draw
Moisten, then pull both standing lines apart. The wraps roll up into a tight barrel with the two tags sticking out of its middle. Trim close.
Common faults
Joining very different thicknesses
The thin line's wraps can't grip the thick line's barrel; the knot slips at a fraction of its rated strength.
Fix: The blood knot wants the two diameters within a step or so of each other. For bigger jumps — leader butt to fine tippet — use the surgeon's knot instead; forgiving mismatches is its whole job.
When you'll use it
- Building tapered leaders at home: butt to mid sections, where slimness helps turnover
- A neat repair mid-leader when both ends are close in thickness
- Anywhere a bulky join would catch weed or the rings
Related
Sources & how we know this (2)
- Blood knot construction: 5–7 turns per side, tags tucked through the central gap in opposite directions, barrel formation
Animated Knots by Grog — Blood Knot · 2026-07-11 - Blood knot preferred for similar diameters and slim profile; surgeon's preferred for mismatched diameters and field conditions
MidCurrent — Which knot: blood knot or surgeon's? · 2026-07-11
Draft reference — pending review.