Loop-to-loop connection
Knot · Last reviewed 2026-08-10
Not a knot at all but a way of joining two looped ends — and the fastest reliable connection there is, provided it is made the right way round.
A loop-to-loop connection joins a main line with a loop in it to a hooklength or leader with a loop in it. There is no knot tied at the waterside: the loops interlock, and a hooklength can be changed in five seconds with cold hands in the dark.
That convenience is the whole reason it exists. Hooklengths are made up at home, with loops tied carefully in good light, and carried ready to use. It also means a hooklength that has been damaged can be replaced instantly rather than at the cost of ten minutes of tying.
There is exactly one thing to get right, and it is the thing most often got wrong. The loops must be passed through each other so that they form a neat SQUARE where they meet. If one loop is passed through the other and then over its own end, the result is a lark's head — a girth hitch — which grips across one loop at a single point and cuts it under load.
- Used for
- Joining two lines
- Holds in
- Monofilament, Fluorocarbon, Fly line, Backing
How to tie it
These written steps are the instruction. The diagram supports them.
- Pass the loop on the hooklength through the loop on the main line.
- Then pass the FAR END of the hooklength — the hook end — through the main line's loop as well, coming from the same side.
- Draw both lines apart gently and watch how the loops meet.
- Check the shape: correctly made, the two loops form a neat square where they cross. If one loop is wrapped around and gripping across the other, undo it and start again.
- Draw the connection up firmly once the square shape is confirmed.
- 1. Start with a loop on each line — main line on one, hooklength on the other.
- 2. Pass the hooklength loop through the main line loop.
- 3. Pass the far END of the hooklength through its own loop, and draw up. The two loops interlock squarely.
- 4. WRONG: passing the far end through the MAIN LINE loop makes a lark's head, which grips and cuts.
Joining two loops, and the join to avoid
Line connection · Verified — every stage checked against a canonical reference — reference: How to Tie Fishing Knots — uni, blood, improved blood, surgeon's and loop knots · signed off by AI editorial review (Sprint 54) — every stage checked against the reference's numbered steps, rendered and inspected on 2026-08-18
Describe this diagram in words
Four panels. Panel one: a loop on the end of the main line and a loop on the end of the hooklength, separate. Panel two: the hooklength loop passed through the main line loop, in front of its near strand and behind its far one. Panel three, labelled correct: the two loops drawn up square, each passing through the other, so that neither closes around a single strand and the load is shared across two bends. Panel four, labelled wrong: the hooklength wrapped around one side of the main line loop instead, both its legs leaving on the same side — a lark's head, which grips one strand and cuts into it under load.
How this drawing was produced
Redrawn in Sprint 54. Sprint 40 recorded that this diagram's whole teaching purpose is to distinguish a square interlock from a lark's head, that its notes claimed the distinction had been confirmed, and that the drawing was incapable of expressing either. It now shows both: panel three is the correct interlock and panel four is the lark's head, drawn side by side and labelled. The previous version also clipped the word DRESSED off the canvas and placed two stage markers on top of the figure.
Finishing it properly
- Look at the shape before drawing it up. A square means correct; anything else means undo it.
- Keep both loops small — the smaller the loops, the less leverage at the join.
- Check the loops themselves for wear before connecting; a loop-to-loop is only as good as the two loop knots.
How it fails
The failure is a lark's head — also called a girth hitch — where one loop wraps around and grips across the other rather than interlocking with it. It looks broadly similar at a glance, it holds perfectly well at first, and under load it cuts into the gripped loop at a single point and parts. This is a visual check that takes two seconds and it should be made every single time. The other failure is a loop that is far too large, which increases the leverage at the crossing point.
Chosen for speed and for changing hooklengths, and the failure that looks correct
A loop-to-loop is selected not because it is the strongest connection available but because of what it lets you do, and that is a legitimate basis for choosing a knot.
WHAT IT BUYS. A hooklength can be changed in seconds, without tying anything, with cold wet hands, in the dark, on a boat that is moving. Pre-tied hooklengths can be made up at home and stored ready, and swapping between them costs nothing. On a match, on a beach at night, or on a boat where every minute of the tide matters, that is worth more than a marginal difference in breaking strain.
IT IS ALSO HOW FLY TACKLE IS ASSEMBLED. Fly line to backing, fly line to leader, and leader to tippet are all commonly loop-to-loop connections, and the reason is the same: components are manufactured with loops, assembled without tools, and changed without dismantling anything.
AND IT WORKS ACROSS A DIAMETER STEP, which is where it beats a blood knot outright. Connecting a heavy main line to a fine hooklength through interlocked loops puts no crushing load of one line on the other, so a large step is not a problem. That is a genuine selection reason rather than a convenience.
THE FAILURE MODE IS THE WHOLE OF THE SKILL AND IT IS DECEPTIVE. Done wrongly, one loop wraps around and grips across the other — a lark's head, or girth hitch — instead of the two interlocking. It looks broadly similar at a glance. It holds perfectly well at first. And under load it cuts into the gripped loop at a single point and parts, usually on the best fish of the session.
THE CHECK IS VISUAL AND TAKES A SECOND. Correctly made, the two loops meet in a neat SQUARE where they cross. If one loop is wrapped around the other rather than passing through it, undo it and start again. That single check is the reason to prefer this connection or to avoid it, and it is worth making every time rather than when it feels necessary.
WHERE NOT TO CHOOSE IT: anywhere the connection must pass through rod rings under load repeatedly, since it is bulkier and more prone to catching than an in-line join, and anywhere the loops themselves are of doubtful construction — a loop-to-loop is only as good as the two loops in it.
Practitioner consensus
Widely and independently recommended by experienced anglers and specialist sources. This is real angling knowledge, not proof: controlled evidence for it is limited, and FishingHQ records it as convention rather than as a demonstrated effect.
- Sea Angler — Bauer Media (Specialist angling publication)Relied on for: Established terminal tackle and knot practice in sea angling.States this directlyCitation checked — the work exists and is described correctly
- IGFA International Angling Rules and World Record Requirements — International Game Fish Association (Angling or fisheries organisation)Relied on for: Line class conventions and terminal arrangements in recognised sport fisheries, including leader and connection practice.Background and mechanism onlyPassage read and verified
Where to go next
Where it is used
- Pole fishingThe rig meets the elastic connector by loop, and the hooklength meets the rig by loop, so a pole angler makes two loop-to-loop joins before fishing and remakes one of them every time the hooklength goes.
- Saltwater fly fishingThe same join, changed more often, because a coastal fly fisher swaps between a floating and a sinking leader far more readily than a stillwater trout angler swaps lines.
- Stillwater fly fishingFly line to leader, made once and remade rarely, and the join that has to pass through the rings without catching. The loop-to-loop is the connection this catalogue records for fly line and backing.
- Coarse fishingThe British and Irish tradition of freshwater angling for species other than salmon and trout — and the most accessible way into fishing there is.
What these connections rest on (4)
Practitioner consensus — 4 connections
Widely and independently recommended by experienced anglers and specialist sources. This is real angling knowledge, not proof: controlled evidence for it is limited, and FishingHQ records it as convention rather than as a demonstrated effect.
Pole fishing
Which knot a kind of fishing conventionally uses is established practitioner knowledge that converges across independent traditions and independent state agency guides, and it is labelled as consensus rather than as tested result. Nothing here ranks knots by strength: see `why-knot-strength-tables-disagree` for why that number does not exist.
- Freshwater Fishing — Macdonald & Jane's, 1975 (Specialist angling publication)Relied on for: Comprehensive British freshwater angling practice: terminal arrangements, leaders, droppers and the knots each is made with.States this directlyCitation checked — the work exists and is described correctly
- Coarse Fishing — A. & C. Black, 1912 (Specialist angling publication)Relied on for: Classical coarse angling practice, including hooklength attachment, loops and the shotting arrangements they carry.States this directlyCitation checked — the work exists and is described correctly
Saltwater fly fishing
Which knot a kind of fishing conventionally uses is established practitioner knowledge that converges across independent traditions and independent state agency guides, and it is labelled as consensus rather than as tested result. Nothing here ranks knots by strength: see `why-knot-strength-tables-disagree` for why that number does not exist.
- Still Water Fly-Fishing — Andre Deutsch, 1952 (Specialist angling publication)Relied on for: Stillwater fly practice including leader construction, droppers and the joins between line, leader and tippet.States this directlyCitation checked — the work exists and is described correctly
- Trout & Salmon — Bauer Media (Specialist angling publication)Relied on for: Long-running published description of British game angling practice, including leader and tippet construction.States this directlyCitation checked — the work exists and is described correctly
Stillwater fly fishing
Which knot a kind of fishing conventionally uses is established practitioner knowledge that converges across independent traditions and independent state agency guides, and it is labelled as consensus rather than as tested result. Nothing here ranks knots by strength: see `why-knot-strength-tables-disagree` for why that number does not exist.
- Still Water Fly-Fishing — Andre Deutsch, 1952 (Specialist angling publication)Relied on for: Stillwater fly practice including leader construction, droppers and the joins between line, leader and tippet.States this directlyCitation checked — the work exists and is described correctly
- Trout & Salmon — Bauer Media (Specialist angling publication)Relied on for: Long-running published description of British game angling practice, including leader and tippet construction.States this directlyCitation checked — the work exists and is described correctly
Coarse fishing
Categorical placement, though the same connection is universal in fly fishing.
- Freshwater Fishing — Macdonald & Jane's, 1975 (Specialist angling publication)Relied on for: Hooklength practice in coarse angling.Citation checked — the work exists and is described correctly
- Coarse Fishing — A. & C. Black, 1912 (Specialist angling publication)Relied on for: Prepared hooklengths in earlier coarse practice.Citation checked — the work exists and is described correctly
Worth understanding first
What these connections rest on (1)
Practitioner consensus — 1 connection
Widely and independently recommended by experienced anglers and specialist sources. This is real angling knowledge, not proof: controlled evidence for it is limited, and FishingHQ records it as convention rather than as a demonstrated effect.
Joining two lines: what the join has to survive
A mechanism edge from a record to the reasoning beneath it. How knots and rigs behave is established practitioner knowledge converging across independent angling traditions, and is labelled as consensus rather than as tested result.
- Freshwater Fishing — Macdonald & Jane's, 1975 (Specialist angling publication)Relied on for: Comprehensive angling practice including knots, leaders, terminal tackle and the reasoning behind rig arrangements.States this directlyCitation checked — the work exists and is described correctly
- Still-Water Angling — MacGibbon & Kee, 1953 (Specialist angling publication)Relied on for: Stillwater angling practice including terminal tackle, hook holds and the mechanics of playing fish.States this directlyCitation checked — the work exists and is described correctly
Instead of this
- Blood knotA blood knot gives a slimmer join that runs through rings; a loop-to-loop can be changed in five seconds with cold hands. Which matters depends on whether you are casting or swapping.
- Double overhand loopThe loop knot exists to make the loop-to-loop connection possible; neither is much use without the other.
- Nail knotThe connection most fly anglers now make with a factory welded loop, and the reason to keep this one. A loop-to-loop is quicker, field-repairable and can be changed in seconds; a nail knot is markedly smoother through the tip ring, which matters when a fish is running and the join is travelling. A failed factory loop also leaves a fly line with a bare end and no loop to interlock with.
What these connections rest on (3)
Practitioner consensus — 3 connections
Widely and independently recommended by experienced anglers and specialist sources. This is real angling knowledge, not proof: controlled evidence for it is limited, and FishingHQ records it as convention rather than as a demonstrated effect.
Blood knot
The trade-off is described independently across traditions.
- Still Water Fly-Fishing — Andre Deutsch, 1952 (Specialist angling publication)Relied on for: Leader construction using blood knots.Citation checked — the work exists and is described correctly
- Freshwater Fishing — Macdonald & Jane's, 1975 (Specialist angling publication)Relied on for: Line-to-line joins in coarse practice.Citation checked — the work exists and is described correctly
Double overhand loop
The two are described together across the literature.
- Freshwater Fishing — Macdonald & Jane's, 1975 (Specialist angling publication)Relied on for: Loop knots and loop-to-loop connections.Citation checked — the work exists and is described correctly
- Trout & Salmon — Bauer Media (Specialist angling publication)Relied on for: Loop connections in game angling practice.Citation checked — the work exists and is described correctly
Nail knot
Fly literature treats these as the two answers to the same connection and separates them on profile and field-repairability, which is what the choice actually turns on.
- Still Water Fly-Fishing — Andre Deutsch, 1952 (Specialist angling publication)Relied on for: Stillwater fly practice: leader construction, teams of flies on droppers, and the joins between backing, fly line, leader and tippet.States this directlyCitation checked — the work exists and is described correctly
- Trout & Salmon — Bauer Media (Specialist angling publication)Relied on for: British game angling practice, including leader and tippet construction and the fly-line connections it rests on.States this directlyCitation checked — the work exists and is described correctly
History and culture
What these connections rest on (1)
Practitioner consensus — 1 connection
Widely and independently recommended by experienced anglers and specialist sources. This is real angling knowledge, not proof: controlled evidence for it is limited, and FishingHQ records it as convention rather than as a demonstrated effect.
Nylon, and what synthetic line changed
Where a terminal arrangement came from and what it displaced, drawn from the angling literature and from widely restated practitioner accounts rather than from scholarship.
- Freshwater Fishing — Macdonald & Jane's, 1975 (Specialist angling publication)Relied on for: Comprehensive angling practice including terminal arrangements, leaders and knots, and the development of each within the sport.States this directlyCitation checked — the work exists and is described correctly
- Still-Water Angling — MacGibbon & Kee, 1953 (Specialist angling publication)Relied on for: Mid-twentieth-century angling practice written across the change to synthetic line, covering terminal arrangements and the materials they depend on.States this directlyCitation checked — the work exists and is described correctly
Sources for this page
- Freshwater Fishing — Macdonald & Jane's, 1975 (Specialist angling publication)Relied on for: The loop-to-loop connection and the requirement that the loops interlock squarely.States this directlyCitation checked — the work exists and is described correctly
- Trout & Salmon — Bauer Media (Specialist angling publication)Relied on for: That loop-to-loop connections are standard for joining leaders to fly lines in game angling practice.States this directlyCitation checked — the work exists and is described correctly
How FishingHQ labels evidence is explained in the evidence policy.