Information: Japanese Line Size “Gou” and Pond Test Strength

When you check Japanese rods, reels and lines you may see Japanese size “Gou” – written as ”号” in Japanese – and wonder, what is it? How strong is it in Pond Test?

As I am one of the Japanese angler in overseas I often encountered to the same issue.

Here I introduce you some information about Japanese size “Gou” and Pond Test strength for “Gou”.

Traditional Japanese Line Size “Gou (号)”

This is the most used line size for long while. This entity is mainly used to show how thick the line is, and it is actually based on the line’s weight originally.

in 1947 one of the biggest fishing line maker TORAY made the first mono line “Ginrou” in Japan, and they established to as 1 Gou = 0.165mm (diameter of a mono line), and it is used on most of line maker in Japan now a days.

However this guide was only to mono-nylon line, so actually, even though some fluorocarbon and braids line have Gou, those can have similar, but different diameter than mono lines. And that’s why often when you see the line capacity of Japanese reels capacity of the same Gou of mono, fluoro and braids are different.

But finally in 2010, JAFTMA – Japan Fishing Tackle Manufacturers Association has established the common guideline for mono, fluoro and braids.

“Gou (号)” and line diameter

Here is the list of how thick Gou (shown as #) are below:

* Strength is basic and average, which can be different on each brands / models.

Calculation of Gou and Pond Test

In English countries, as you know, the line are shown as pond test, lb. However, because it just says the strength of the line not weight or diameter of the lines, you may have already experienced such situations – in my experience, I bought a reel saying “10lb mono line capacity: 200m” and bought a 10lb mono line, but I could only wrap 150m of the line to the reel. Of course I bought 200m line, the rest of 50m line were left and did not have any way to use them.

So, Gou the entity of diameters can be simple and useful to know line capacity. But in this case, you cannot expect the same Goued line has the same strength, as the quality and manufacturing can be differed by brands.

Usually, Gou can be transferred to lb by 4 times, meaning if a line is 2 Gou it can have 2 x 4 = 8lb pond test strength. Fluoro lines are actually a bit weaker than Mono-Nylon lines, so the actual pond test value is a bit lower than that, but not much.

And braids are told that it can be calculated by 10 times than the Gou number, meaning if a braid line is 2 Gou it can be 2 x 10 = 20lb pond test strength. Therefore when I purchase lines in Australia and wrap them to Japanese reels, I usually calculate the line capacities based on these.

So, if you want to attach Japanese line to your reels bought from local stores, I can expect totally opposite calculation, like if your reel has 10lb = 200m braid line capacities, I would buy 1 Gou 200m braid line from Japan. (Sorry to say, but cannot guaranteed.)

Actual Pond Test Value for Gou

But actual pond test value of the same Gou value can be different by brand, of course. It can also be differed by lines even in the same brand. And as technology is advanced day by day, especially the braid lines are much stronger than that now. Like, YGK Yoz-ami sells 2 type of game fishing line named “Galis Ultra Jigman” and “G-Soul X8 Upgrade”, and those are both 8 lines braided. But Ultra Jigman’s strength is this, 1 Gou = 18lb, and G-Soul ‘s 1 Gou = 22lb. Of course, they both have the same diameter.

In fishing, it is told that the narrower line is better, because you can cast further, the jig or sinker can be sunk faster, and the bite sign can be more obvious than thicker lines. So when I select lines, I often check the Gou and lb value, and tend to select the stronger line in the same Gou value, especially for small game fishing such as Bass, Eging etc.

At last, here are some lines recommended from me and people around me.

<PE (Braid) Line>

Small Game:

• YGK G-soul X8 Upgrade
• YGK GALIS Super Jigman x8

Game Fishing / Jigging

• YGK GALIS Ultra Jigman WX8
• YGK GALIS Ultra Castman WX8
• SHIMANO OCEA EX8 PE
• DAIWA Mega Sensor 12 Braid

<Fluoro Carbon Line>

• Seaguar R18 Fluoro Limited
• VARIVAS VEP Shock leader
• Seaguar FXR Ship

<Mono / Nylon Line>

• SUNLINE Saltwater Special System Shock Leader Nylon
• DAIWA Morethan Leader X-treme Type-N