Upstream Worm Lines

The Importance of Line Sag

When the upstream worm technique was in common use, anglers fished with a horsehair line. Horsehair is not very strong, so to make a line with sufficient strength, multiple hairs were twisted together. The resulting line was heavier than most modern fly lines and much heavier than modern tenkara lines.

However, that was not entirely a bad thing. The heavy line produced significant line sag. I have come to believe that line sag is a critical element in tenkara fishing and and is the critical element in upstream worm fishing.

Angler fishing with long rod and horsehair line.Sag of a horsehair line

When I first tried Ultralight Worm Fishing (which I should have called The Upstream Worm, but at that time I didn't realize it was a recognized technique that had a name), I was sure a tenkara line would allow me to make the cast. After all, it casts nearly weightless flies without any added weight.

It turns out using a tenkara line provides three tremendous benefits relative to the light lines used in either keiryu fishing or spin fishing:

  • It has enough weight to make the cast without split shot. Not using split shot nearly eliminates getting snagged in the rocks on the bottom, which can be a significant problem when keiryu fishing in shallow streams. With no added weight on the line, the worm goes with the water's flow over and around rocks. It also achieves a much more natural drift.
Hi-vis line showing sag and curvature near the end of the lineSag of a light tenkara line.
Notice the curve in the last few feet of line.
  • The curve caused by the sagging line is an extremely sensitive strike indicator. As the worm drifts down towards you with the current, lift your rod tip enough to keep the end of the hi-vis tenkara line off the surface, but not so much that it pulls the worm faster than the current. 
  • Keeping the worm drifting at the speed of the current will keep a bit of sag in the line. When a fish takes the worm, the line will stop. If you are smoothly moving the rod tip at the speed of the current, the line will straighten. Since the worm usually goes over and around rocks rather than getting caught on them, if the line straightens it is almost certainly a fish. The line might not just straighten, it might move to the side or shoot upstream by as much as a foot. If a fish takes the worm, you'll see it. If your worm is in an eddy or a very slow pool, the indication of a strike might be extremely subtle, perhaps just a slight twitch or wiggling of the line. In general, the slower the current, the more subtle the strike. Concentrate on the curvature of the line near the water's surface.
White line against dark water background, showing line sagCurve caused by line sag provides a bit of slack.
  • The line sag provides a bit of slack so the fish can take the worm and not feel immediate tension on the line. A trout will spit out a worm if it feels tension on the line! I am convinced that feeling tension is a more immediate trigger that something is wrong than feeling the hook (although I would still use small hooks - which will be covered in a later section). When a fish takes the worm, you will see the line straighten or move before the fish feels tension. You'll know it's there before it knows you're there.

For upstream worm lines I have used size 2.5 and size 3 hi-vis fluorocarbon and a Fujino tapered nylon line. Some of the tenkara rods that would be appropriate for fishing the upstream worm would do better with a size 3.5 line.

Although I have not yet tried size 3.5 or size 4 lines for upstream worm fishing, I think they should work quite well. The heavier lines will create a bit more line sag, and the greater sag will tend to pull the worm faster than the current. However, they are still lighter than most of the horsehair lines used a hundred years ago, so I cannot imagine that they would pull the worm too fast to be effective. I say most because the horsehair line Charles Cotton used was so light that not even all modern tenkara rods will cast it well. Trying his line with the Upstream Worm is on my "to do" list.

Slightly heavier lines may yield a benefit that more than offsets any problems caused by greater line sag. One of the casting methods that was described in Clear Water Trout Fishing With Worm by Sidney Spencer (which, by they way, is the best book on fishing the upstream worm I have found) is basically a pendulum cast. I have found a pendulum cast to be very effective, and with practice it can be very accurate and allow a very gently entry of the worm into the water. To date I have only done it with split shot to provide the weight required to get the pendulum effect - which was before my Ultralight Worm Fishing trip. Casting is covered in the Ultralight Worm Fishing article.

Hi-vis Yamatoyo tenkara line - bright chartreuseYamatoyo tenkara line - fluorescent chartreuse
Lo-vis green line, since discontinuedSunline tenkara line
fluorescent orange

I have caught lots and lots of fish with hi-vis fluorocarbon lines. It is critical to keep the bright line off the water's surface at all times, though. Don't even let the line touch at the end of your cast and then pick it up immediately. Don't let it touch the water at all! If you have to shorten your line and lengthen your tippet a bit, do so.

Still, since the upstream worm - also called the clear-water worm - is generally fished in low, clear water, you will need all the stealth you can muster. Using a longer tippet has advantages beyond just keeping the hi-vis line off the surface, it also keeps it further away from the fish.

TenkaraBum Home

The Upstream Worm

Upstream Worm Rods

Upstream Worm Lines and Line Sag

Upstream Worm Hooks and Hooking

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"Be sure in casting, that your fly fall first into the water, for if the line fall first, it scares or frightens the fish..." -
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