Japanese Fishing Line Standards

Here is the standards of fishing lines, stated by Japan Fishing Tackle Manufacturers Association (JFTMA).

Monofilament line

This is the chart of thickness standard of monofilament line.

Japanese unique unit of gou and diameter in mm can be easily refered.

Gou (# / 号)	Diameter (mm)
0.1	0.053
0.15	0.064
0.2	0.074
0.25	0.083
0.3	0.090
0.35	0.097
0.4	0.104
0.5	0.117
0.6	0.128
0.8	0.148
1.0	0.165
1.2	0.185
1.5	0.205
1.75	0.220
2.0	0.235
2.25	0.248
2.5	0.260
2.75	0.274
3	0.285
3.5	0.310
4	0.330
5	0.370
6	0.405
7	0.435
8	0.470
10	0.520
12	0.570
14	0.620
16	0.660
18	0.700
20	0.740
22	0.780
24	0.810
26	0.840
28	0.870
30	0.910
40	1.050
50	1.170
60	1.280
70	1.390
80	1.480
90	1.570
100	1.660
110	1.740
120	1.810
150	2.030
200	2.340

Difinition and explanation of JAFTMA

• This is the standard thickness for monofilament lines of nylon, fluorocarbon and polyester.
• The tolerance of the diameter: the minimum or maximum diameter does not exceeds the adjucent class (gou) thickness. The actual diameter should be targeted to meet the standard.
• The strength indication is decided by each company or brand.
• The way of measurement is to scale the diameter at three different angles on one point of the line.

The link to the summary PDF (in Japanes).

This standard is based on this.

1 gou = 200 denir

Denir is the unit , equals to the weight in gram per 9000m.

NOTE; Though the actual strength varies depend on the line material, the general reference is as below.

1 gou (0.165 mm) = 4 lb or 1.8 kg

2 gou (0.235mm) = 8lb or 3.6 kg

5 gou (0.370mm) = 20lb or 9 kg

And thicker lines does not increase the strength linearly.

10 gou (0.520mm) = 35lb or 16 kg

20 gou (0.740mm) = 60lb or 27 kg

Braided line

This is the chart to refer gou and thickness diameter in mm. Please note that the thickness and strength is added by the author and just for the reference.

Gou (# / 号)	Denir (gram for 9000m)	Thickness (mm) & Strength (kg) Reference only
0.1	20	0.05mm, 1.8 kg
0.15	30
0.2	40
0.25	50
0.3	60
0.35	70
0.4	80
0.5	100	0.12 mm, 4.5 kg
0.6	120
0.7	140
0.8	160
1	200	0.17 mm, 9 kg
1.2	240
1.5	300
1.7	340
2	400	0.24 mm, 18 kg
2.5	500
3	600
4	800
5	1000	0.38 mm, 36 kg
10	2000	0.54 mm, 59 kg
12	2400
15	3000
20	4000	0.76 mm, (strength varies by brand)
25	5000
30	6000	0.97 mm, (strength varies by brand)

Difinition and explanation of JAFTMA

• This chart is the tickness standard of braided line.
• This is for braided line, which includes coating and pigment weight.
• As for the unit of standard, it uses denir. And 1 gou equals 200 denir.
• The tolerance of this standard; the minimum or maximum denir does not exceeds the adjucent class (gou).

Braided line's diameter is very hard to measure. It can be easily compressed and deformed. But it has certain volume. For definition wise, JAFTMA uses denir for braided line in Japan.