Non-Slip Mono Loop
Also known as: Kreh Loop, Lefty's Loop
fishing knot
Some lures and flies swim or wobble far more naturally when they're not cinched tight against the line by a fixed knot - the eye needs room to move independently for the lure's built-in action to show at its best. Fishing writer and casting instructor Lefty Kreh popularized this loop knot specifically for that reason: a fixed overhand loop provides the security of a snug, non-slipping connection at the standing line, while the lure end swings freely inside its own loop rather than being pinned tight.
The method ties a loose overhand knot first, well back from the line's end, then threads the tag end through the lure's eye and back through that same overhand loop before wrapping around the standing line and finishing through the original loop - a sequence that keeps the loop's size adjustable right up until the final pull locks everything in place.
Getting the loop size right matters more here than with most fixed knots: oversized, it makes the lure's action sloppy and increases the risk of the loop snagging on the hook or on debris; undersized, it starts to behave more like a fixed knot and loses much of the free-swing benefit that's the entire reason to tie a loop knot in the first place.
Fly anglers and lure fishers who've noticed a particular streamer or crankbait swim noticeably better on a loop connection than a cinched-down knot are responding to a real, well-documented effect - not every lure benefits from it, but for those that do, the difference in action and resulting strike rate can be genuinely significant.
Kreh developed and popularized the knot in the latter half of the twentieth century as part of a broader body of practical, field-tested casting and rigging instruction he was well known for across both fly and conventional tackle, rather than as a purely fly-fishing technique - it appears just as often in spinning and baitcasting instruction for exactly the same reason it works in fly fishing: certain lures and hooks perform better with a freely pivoting connection than a rigid one, regardless of what kind of rod is casting them.
What separates the non-slip mono loop from a simple, unlocked loop knot is that initial overhand knot forming a fixed anchor point on the standing line - without it, a plain loop tied directly around the standing line would slowly cinch itself down toward a fixed knot under repeated casting and fighting pressure, defeating the whole purpose. That anchor is what lets the loop stay genuinely open and free-swinging for the life of the knot rather than gradually tightening the way an improvised loop without a locking point would.
How to tie the Non-Slip Mono Loop
Tie a loose overhand knot roughly fifteen centimeters from the line's end, without tightening it.
Strength & security
Approx. strength retained: 90-95% of line strength
Popularized by angling writer Lefty Kreh, this loop knot lets a lure or fly swing and move naturally in the water, since the connection isn't cinched down tight against the eye - a genuinely different and often more effective presentation than a fixed knot for lures that rely on natural swimming action.
Cautions: The loop must be sized correctly for the lure - too large and action becomes sloppy or the loop can catch on hooks or debris; too small and much of the free-swing advantage over a fixed knot is lost.
Alternatives
- Improved Clinch Knot
A fixed, cinched-down knot rather than a loop - use it when a rigid connection is actually preferred, such as with lures whose action doesn't benefit from a free-swinging attachment.
FAQ
Who popularized the non-slip mono loop?
Angling writer and casting instructor Lefty Kreh, which is why it's also commonly called the Kreh loop or Lefty's loop.
Why use a loop knot instead of a fixed knot like a clinch knot?
Some lures and flies swim more naturally when the eye can move somewhat freely rather than being cinched tight - the loop knot preserves that natural action while still holding securely at the standing line.
How do I know if the loop is the right size?
Too large and the lure's action becomes sloppy, or the loop can catch on the hook or debris; too small and it starts behaving like a fixed knot, losing the free-swing benefit - some trial and error per lure is normal.
Does the non-slip mono loop work with fluorocarbon as well as monofilament?
Yes, though fluorocarbon's added stiffness means the wraps need more careful, even tightening to seat properly, and wetting the knot before the final pull matters even more than with softer monofilament to avoid friction damage.
Is this knot suitable for topwater lures specifically?
Yes - topwater plugs that rely on a walk-the-dog or side-to-side action are a classic use case, since the free-swinging loop lets the lure's nose move independently of the line in exactly the way that action requires.
Can the non-slip mono loop be tied quickly on the water?
With practice, yes - it's a bit more involved than a basic clinch knot since the loop size has to be set before the final cinch, but most anglers who tie it regularly can manage it in well under a minute even on a moving boat.
Can the non-slip mono loop be re-tied smaller if the first attempt comes out too big?
Yes - since the loop size isn't locked until the final pull, most anglers simply back the wraps off, slide the loop to the size they actually want, and re-cinch, rather than cutting the leader and starting the whole knot over from scratch.