Tenkara Fluorocarbon

My association with Esoteric Tackle means I have a whole range of lines to consider. I don't have every line on the market but I have a fair selection. Let's start with the Japanese numbering system. Line numbering goes back to the silk trade. You can find a detailed discussion at Tenkara Times. (Linked with approval from Oleg.)

In essence there are two ways of determining the Japanese "Gou" number. The "rule of thumb" is to divide the lb rating by 4. Thus 12lb is Gou 3 (#3). The other way is on diameter so #3 should be 0.285mm. It's all very odd because 12lb and diameter don't always match up. In the west we'd measure diameter by direct measurement but, as I understand it in Japan they take a standard length of line and measure its weight, from that they calculate its average diameter. So this might explain the difference.

The favoured line diameter, by many people, is #3 or 0.285mm so I got together all my lines that are in that ball park.

Sunline Buttobi, Yamatoyo, YGK, Nissin Pals ONI, Sunline BMS lines were all put to the test. Here is what the micrometer has to say:

Line Stated Measured
Yamatoyo #3, 0.285mm 0.321mm
Sunline Buttobi #3, 0.285mm 0.320mm
YGK #3 0.321mm
Nissin Pals ONI #3 0.314mm
Sunline BMS 10lb, 0.290mm 0.291mm

Isn't that interesting? The proclaimed Tenkara lines all understate their measured diameter. The bass fishing (not sea fishing) line Sunline BMS is pretty much spot on. The specific Tenkara lines are closer to #3.5 (0.310mm) if you go entirely on diameter. In fact they are slightly thicker and therefore heavier. We all know that heavier fluorocarbon lines are easier to cast but sag more.

Rightly or wrongly, casting a lighter rated line has "bragging rights" and is used as a measure of how well a person can cast. Tenkara lines are at least #0.5 thicker than they are stated to be, based on diameter alone.

The next size up Sunline BMS at 12lb has 0.310mm on the spool and measures in at 0.311mm. This is a #3.5 according to diameter but using the alternative "rule of thumb" guide it is a #3. In terms of casting the 12lb Sunline BMS is very similar to the Tenkara lines with a #3 rating. The "rule of thumb" seems to have some merit. Perhaps that is why the 12lb Sunline BMS it is my preferred line in the range? In terms of diameter it is a better match for the Tenkara specific lines.

Certainly it is food for thought. Here I have presented empirical evidence that stated Gou numbers are more complicated than just a measure of diameter.

If someone tells you that "sea fishing fluorocarbon" is useless for Tenkara the chances are they have not been comparing like with like. They would also be wrong about Sunline BMS being for sea fishing. I've been seen casting almost 2 rod lengths of #3 Sunline BMS (10lb), fly first cast, on Llangollens water. That would be the equivalent of #2.5 of a Tenkara specific line with my Strooan rod. Bragging? No, that is my standard set up for that water. It does demonstrate that these lines are fit for purpose. They even have a built in bite indicator and are more stealthy. My local rivers hold fish that spook when the brightly coloured fluorocarbons come anywhere near the water. That's why I use this particular line. Nothing wrong with the others.

I maintain that it doesn't matter which fluorocarbon you choose they are all pretty much the same. In terms of stiffness there's nothing in it, when you have the same diameter. The only difference is the colour. Choose the colour you can see best or spooks your fish the least. Use whatever tackle works for you, in your situation. Use what you are confident with. Confidence is a huge part of fishing but rarely mentioned.

For the long term storage for lines I prefer spools. On the river, I prefer easy keepers. With regards kinks from easy keepers, if you have quality line the kinks come out easily after only such a short storage. Easy tip, don't wind them too tight! With any storage of the line you have to stop, stretch your line. That gives you a chance to assess the water ahead before ploughing in. Does anyone not give their a line a stretch after taking it off a spool? I always do. It is just that the spool is more bulk to carry, or drop.

Anyone who wants to send me a sample of #3 lines for testing and to add to the list please get in touch. I'll even add them to the shop if there is demand and I can source them. I can not recommend any specific fluorocarbon line. They are all basically the same and that is to say, very good. More importantly I'm not rubbishing any line or tackle that you prefer to use.


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