Industrial espionage, according to the Byzantine historian Procopius, conspicuously came into being in the early 550s, when a couple of wily Nestorian monks presented the Roman emperor Justinian with a number of eggs. Justinian had been keen to break the trade monopoly controlled by his great enemy Persia of a material whose value at times in ancient Europe exceeded that of gold. The two monks had informed him that they could help him do so. And thus on their return from a grueling trek to China, they found themselves amply rewarded by the grateful emperor when they provided him with the means for making silk.
A couple of hundred years before Justinian was able to put the silkworm eggs he had acquired to good use and begin silk production in Byzantium, the jealously guarded secret of making the exquisite material made its way to Japan. The earliest chronicle of Japan, the third-century Chinese record known as the Wei Zhi, mentions sericulture being practiced in Japan. The technique for raising silkworms to make silk is believed to have arrived in Japan from China via the Korean peninsula. The practice was certainly able to flourish in its new home since the Japanese climate lends itself particularly well both to raising silkworms and growing mulberry trees, on whose leaves the insects feed.
The capacity to produce great quantities of mulberry leaves is certainly advantageous given the utterly rapacious appetites of silkworms. Silkworms are born to eat. And during their brief lives of around thirty-five days, the larvae assiduously and constantly eat their way to a body-weight increase of 10,000-fold. To produce 1 kilogram of silk, 104 kilos of mulberry leaves have to be downed by 5,500 of the wriggling eating machines.
After having finally eaten their fill, silkworms are ready to spin their cocoons, producing silk from two glands in the head out of which the silk is expelled as a liquid. Despite their name, silkworms are actually the large caterpillars of moths, and all caterpillars produce silk, but only silkworms produce the lustrous long fiber that can be made into the commercial material. The cocoons are sorted for quality and then immersed in hot water, which frees the silk filaments for winding onto reels and also kills the hapless creatures.
In Japan, silkworms were traditionally reared in family dwellings, such as in the famous World Heritage Site farmhouses of Shirakawa-go and Gokayama in Gifu and Toyama prefectures, which featured huge attic spaces for raising silkworms. When Japan underwent its rapid modernization towards the end of the nineteenth century, sericulture ceased being largely a cottage industry. Japan constructed factories to produce the silk that became a great pillar of the country’s export trade. In the 1920s and 1930s, before nylon was invented, Japan supplied much of the world’s silk used to make silk stockings. As testament to the importance of the silk industry to the newly industrializing Japan, the country’s oldest government-run silk mill, in Tomioka, Gunma Prefecture, established in 1872 with the help of Western technology, is itself a candidate to receive World Heritage Site status.
As with a number of insect species, silkworms are eaten in various parts of Asia. Indeed, the animals are particularly nutritious, and one Chinese researcher has proposed that silkworms could serve as an excellent source of protein for astronauts on deep-space missions since they require little space and water but offer twice the number of essential amino acids as pork. Down to earth, roasted silkworm pupae appear on restaurant menus in China and are also sold there by street vendors. Silkworm pupae are eaten with gusto in Korea, where they are steamed or boiled in cauldrons on the street as beondegi. For anyone not of Korean origin who has smelled silkworm larvae being boiled, it is one of life’s most profound enigmas how anything with an odor that could terrify small children could seriously be regarded as an object of human consumption. And in fact, beondegi tastes exactly like it smells. Apparently. Despite the compunction for journalistic thoroughness, the present reporter sadly has never been able to bring himself to allow beondegi to come anywhere remotely near his palate.
David Capel is a journalist living in Tokyo.