Shaku (尺) and Sun (寸) conversion in cm
1 Shaku = 30.3 cm
1 Sun= 3.03 cm
Convert Japanese units of measurement to centimetres
Convert Shaku and Sun to cm
With our simple calculator you can convert Shaku and Sun to cm and mm and vice versa.
Shaku
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Sun
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Convert centimetres to shaku and sun
cm
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Why are there units of measurement
These are units from the old Shakkanhō system. This comprised standardised values for lengths, areas, weights, etc.
Like most units of measurement, the units were invented in order to find standardised measures for markets and society that are always the same everywhere.
In Japan, lengths are now also given in metres and centimetres. In the field of Japanese swords, however, the traditional unit of measurement has been retained.
Similar units of measurement have been used around the world since the 3rd millennium BC. The oldest known unit of measurement is the Ellewhich was also used in the Roman Empire, for example.
Are shaku and foot the same thing?
Shaku is often equated with the unit foot, which was widely used in our spheres. This is why you often hear the term Japanese foot. However, it is more of a coincidence that the two values converted into cm are roughly the same length. To be more precise, one is 30.3cm, as described above, while an English foot is 30.48cm long. Both units of measurement have different origins.
While the measurement foot actually comes from the length of the foot, the Japanese measurement comes from a hand. In this sense, the character 尺 can be interpreted as a hand with the thumb and middle finger spread apart.
How many Sun are a Shaku?
Similar to our system of mm, cm, etc., the old Japanese system is based on a factor of 10. An excerpt from this system:
Rin = 0.30 mm
Bu =10 Rin = 3.03 mm
Sun = 10 Bu = 3.03 cm
Shaku = 10 Sun = 30.03 cm
Jō = 10 Shaku = 3.03 m
Use with Iaito and Nihonto
It is an old unit and therefore, according to tradition, the usual size for expressing the dimensions of samurai swords. It is therefore the standard for antique katana and tachi. But also for IaitoThe blade lengths of training swords for Iai (also known as Iaido or Iaijutsu) are given in Shaku.
Shaku at Nagasa
Nagasa is the blade length measured from munemachi (the point where the blade ends at the back of the blade) to the tip. This measurement is usually given in the old Japanese unit of measurement. A common nagasa length, for example, is 2.4 shaku, or 72.72 cm.
Typical nagasa measurements for katana today are between 2.0 and 2.45 shaku, i.e. between 60.6 cm and 73.93 cm. For taller Europeans, it is therefore often necessary to choose a length outside the usual standard. Such lengths are available with our Premium Iaito: https://japan-budo.com/iaito-premium/
As a rule, for cost reasons, new students use Iaito up to 2.45 Shaku and as soon as the swordsmanship is consolidated, they switch to an individually suitable measure.
Sun at Tsuka
The length of the sword handle (tsuka) is given in sun as standard. A usual length would be 8.5 sun, i.e. 25.8cm. Long hilts can be over 10 sun long. This would be 1 shaku (30.3cm) and more.
Caution: There are different versions!
Despite the aim of a uniform standard, there are differences. For example, there is a slightly different definition for the units in the textile sector.
The exact definition in cm was not officially established until 1891. There have been slight variations in the interpretation of length over time. The interpretation can vary, especially in historical sources. In some old sources, the converted measurement was only approx. 18 cm.
We always use the above definition!
