How many miles of silk fibre in a Japanese kimono?

By The Kimono Company on 31/05/2014

silk moth, silkworm and silk cocoons

Yes, how many miles of fibre in a silk kimono. But before we try to answer that question, a few words on the fascinating topic of how silk is made.

"With time and patience the mulberry leaf becomes a silk gown". An elegant Chinese proverb, though in practice with a few tons of mulberry leaves, a large number of silkworms and the right conditions, a kimono's worth of raw silk can be produced in a couple of months. Silk, the queen of fabrics, is admired for its beauty, lightness and strength, yet the story of how it is cultivated is even more remarkable.

Although several insect species produce silk, the domesticated silk moth is the only one used for making textiles. A silk moth mates, produces eggs and dies within about a week; once the eggs hatch after 2-3 weeks, the emerging caterpillars (which we call silkworms, though they are not really worms) are fed on fresh mulberry leaves. The silkworm has a voracious appetite, and in just a month it will increase its weight 10,000-fold and shed its skin four times, at which point it is ready to begin spinning a cocoon in preparation for becoming a chrysalis. Silkworms have to be protected from loud noises, temperature changes or strong smells, as these will affect their appetite and the quantity of silk produced.

feeding silkworms in Japan

The silkworm now climbs up a specially designed frame and finds a compartment in which to spin the cocoon around itself, which it does by moving its head rhythmically in a figure-of-eight pattern, secreting a sticky silk filament from two glands in its head. Within a few days, the silkworm spins enough silk to become completely encased in its cocoon.

silkworms making cocoons

The silkworms are then killed inside their cocoons by heat, with some being spared to metamorphose into moths in order to breed the next generation. Cocoons are inspected, sorted and soaked, with only perfectly shaped cocoons being accepted for the next step - reeling. A brush is used to tease out the end of the silk fibre, which, too thin to be used alone, is reeled through an eyelet together with several others to make a single thread, though still only as thick as a human hair. This photo of a silk factory (below, right) was taken in the early 1900s, but modern silk reeling remains labour intensive despite today's better technology.

reeling silk from cocoons

An alternative method of silk cultivation allows silkworms to survive and emerge as moths, with the resulting product being labelled as 'peace' or 'cruelty-free' silk. Allowing the moth to break out of its cocoon results in much shorter strands of silk and a different quality of fabric: it is spun rather than reeled, is softer and fluffier than the conventional fine, shiny silk, it costs more and is slightly discoloured. Even 'cruelty-free' silk is not without ethical concerns, however, because the silkworm, as the world's only domesticated insect, has been selectively bred to be totally dependent on humans for survival.

The silkworm and its cocoon can be put to uses other than silk manufacture:

silkworms on a stick and cocoon skin cleansers

(Left: silkworm snacks on a stick, Beijing market. Right: cocoons as facial cleansers with rejuvenating properties)

silk cocoon dolls

(Above: empty silk cocoons are a popular craft item in Japan)

Finally, then, the answer to our question. Each cocoon contains hundreds of metres of raw silk fibre; estimates vary widely, but let's take a mid-range figure of 600 metres per cocoon. At the Yokohama Silk Museum we discovered that the number of cocoons needed to produce one kimono is 9,000. So, although difficult to imagine, the answer is that around 3,300 miles of silk fibre is needed to make one traditional Japanese silk kimono!

Here are those 9,000 cocoons:

9000 silk cocoons

Tags: japanese kimono | silk kimono | silk | cocoon | silkworm

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