Japanese Unit of Sinker; Gou and its history

This is the reference chart of gou (Japanese unique unit of weight) and gram.

1 gou = 3.75 grams

Gou (号）	Weight (g)
0.3	1.13
0.5	1.87
0.8	3.00
1	3.75
1.5	5.63
2	7.50
2.5	9.38
3	11.25
4	15.00
5	18.75
6	22.50
7	26.25
8	30.00
10	37.50
12	45.00
13	48.75
15	56.25
18	67.50
20	75.00
25	93.75
30	112.50
40	150.00
50	187.50

A bit of history of this unit

In Japan, it was 1891 that we enrolled the meter convention. (This convention was signed in Paris in 1875.)

Until then, people were using the different unit called Shakkanho, such as below.

• Shaku = 0.303 meter
• Tsubo = 3.306 square meter
• Sho = 1.804 liter
• Kan = 3.750 kilogram

Under the weight unit of Kan, there were units as following.

• Kan = 3.750 kilogram
• Momme = 0.375 kilogram (375 gram)
• Fun = 0.0375 kilogram (3.75 gram)
• Rin = 0.00375 kilogram (0.375 gram)

Here you notice that Fun is the same weight as gou.

Since the word of gou is general term for indicating type or size, someone put the Gou indication on the Fun weight.

In the past, these weight was confirmed by the metal samples as below.