I’m getting a lot of inquiries about line strength recently. It’s confusing to me too. I’m sharing some information I know.

Difference in Line Rating

US uses tensile strength by poundage to rate the line.
Europe labels diameter and poundage.
Japan uses the class number which is determined by denir. It is the weight (gram) of the threads to make 9000m of line.

Japan’s class number is as follows.

Class NumberDenir (d)Diameter (mm)

The diameter is only a typical value. The class number is determined by the weight of the line. The diameter and the strength depend on how the line is braided.

Line Strength Indication

Anyway, Japan line does have line strength by poundage (or kilograms) too, even though some indicate that and some don’t. But this poundage is different from US poundage. This is what confuses us.

There are 2 different gauges.

Pound Test – USA

It is indicated like these:

  • PTL
  • TEST (lb)
  • lbT

This poundage asserts that the line does not break at the traction.

Pound Class – JAPAN

It is indicated like these:

  • PCL
  • CLASS (lb)
  • lbC

This poundage asserts that the line does break at the traction.

They look similar, but the poundage can be very different.

Suppose there’s a line which is rated 10 “lbC”. It is guaranteed that it will break at 10 lb. It also means that it can break at 7 lb or 8 lb. But it will never break at 6 lb. So it can be rated 6 “lbT”
So, here is the line rated 10 lbC and 6 lbT.

Japan uses Pound-Class.
US uses Pound-Test.
I don’t know what Europe uses. It seems like Pound-Class.

Also, some Japanese makers use maximum strength and some average. Some indicate MAX or AVE, some don’t. It is assumed that they probably assert maximum strength because it will sell more.
Furthermore, some makers assert “knot strength”. It makes sense because the knot is the weakest part. Even though makers indicate it as knot strength, retailers sometimes mistakenly indicate it as line strength.

It’s really confusing when you want to compare different lines. It’s really up to anglers to determine what’s worth trusting.

Fireline for Comparison

Fireline is US product and it’s selling around the world. Of course in Japan too. But not just as imported line, there’s Berkley Japan who rates the line according to Japan regulations. This one really confuses us because of this poundage difference.

I called Berkley Japan and asked to match which Japan label is which US label.
Fireline has been remodeled recently and Berkley Japan renamed it Super Fireline. It is the same product as what’s called Fireline Original in US.

Here’s a table to compare Japan label and US label, in line with Japan class number.

Japan Regulations

class numberDia meter (mm)

Super Fireline (JAPAN)

Poundage PCLDia meter (mm)
16 lbC?
20 lbC?
24 lbC?
30 lbC?
40 lbC?
45 lbC?
50 lbC?

Fireline Original (US)

Poundage PTLDia meter (mm)
4 lbT0.12
6 lbT0.15
8 lbT0.17
10 lbT0.20
14 lbT0.22
20 lbT0.30

Now, Fireline Japan does not show diameter. Because Japan regulation uses denier (the line weight) to rate braided lines. Berkley Japan rates the lines in class number according to this regulation.

US Berkley measures the line by laser. It should be accurate. You can see the line is much thinner for the class it is rated in.

The actual diameter of PE lines in Japan can be very different in the same class. Because it is the weight of the line that it’s rated by. The diameter can be different depending on how it’s braided. Tight or loose. 8-ply or 4-ply.

By the way, I have ordered Fireline from Chinese site before. Just for the hell of it. It was ridiculously cheap. They did deliver OK. But I found that it was braided ridiculously fat and clumsy. I just laughed and threw it away.

Fireline is a coated line. I couldn’t figure out what the weight of the coating effects its rating… But anyway, it’s safe to say Fireline is thin for the class.

You don’t see PE3.0 in US products. This is produced specifically for Japanese market.

Also, Super Fireline “Colored” is produced by Berkley Japan only, responding to the need of Japanese slow pitch anglers by marking the line with different colors every 10 meters.

Anyway, it’s amazing how different the poundage can be. Japanese poundage is 3 to 4 times bigger than US. Actually, the difference is usually a lot less with high-end lines. They have the technology and precise production to make constant uniform lines.
Let’s face it. Fireline is not exactly a high-end line. Fireline is really not braided, so once the coating is damaged it’s very very weak. I use it too for its unique properties to suit slow pitch jigging and for the price, but I renew it every season.