The silkworm was still a rare novelty at the dawn of Japanese history,-just imported, as it would seem, from Korea. The first mention of it is in the annals of the reign of the Emperor Nintoku, who is supposed to have died in A.D. 399. Up till then, the materials used for clothing had been hempen cloth and the bark of the paper-mulberry, coloured by being rubbed with madder and other tinctorial plants. The testimony of Japanese tradition to the foreign origin of silk, and its absence here in earlier ages, go to support the results of modern research to the effect that neither the true silkworm nor the mulberrytree on whose leaves it feeds ever occurs wild in this archipelago. Striking change indeed! Silk has, for at least thirteen hundred years, helped to dress the Japanese upper classes, male as well as female, and has come to form the chief mainstay of the national prosperity.
The Japanese silkworm moth is the Bombyx mori; L.; its mulberry-tree the "white mulberry,"-Morus alba, L. Insect and tree have alike developed several varieties under cultivation. As a rule the trees ars pollarded, and Japanese thrift takes advantage of the space between the stumps to grow small crops of useful vegetables. The branches are generally carried home for stripping. The Japanese silkworm manifests some marked peculiarities at different stages of its life-history. The eggs have extremely fragile shells, for which reason the moths are made to deposit them on cardboard; the worms are sluggish in their habits, and the cocoons smaller and lighter than those of Italy and the Levant, though the silk is but little inferior in quality. Some indeed, from certain filatures in the province of Shinano, is superior on account of its brilliantly white colour. Careless reeling, with consequent irregularity, is the weak point. In many parts of the country, primitive methods of working survive unchanged; in others, foreign machinery has been introduced. Besides the true silkworm, there is another species called yama-mayu, which feeds on the oak-leaf, and produces cocoons of great strength and beauty. Yet another - a wild one, called sukari, whose food is the leaf of the chestnut tree - has less value. The central and northern provinces of the Main Island have from time immemorial been dotted with silk-producing districts. Nothing is so remarkable in the recent industrial development of Japan as the manner in which these districts have spread, until scarcely a rural commune remains without its mulberry plantations. Statistics confirm what any observant eye can notice. During the last twenty years the area planted with mulberry-trees has increased about 200 per cent, and as much as 88,000,000 yen worth of silk has been sent oversea in a single year. What the domestic consumption is, we cannot say; but it must be enormous. Think of the dresses, the sashes, the quilts, the wrappers for gifts, the brocades, the silk crape, the rolls of silk for painting or writing on, and the thousand other uses to which this most beautiful of all fabrics is put. Silk is exported in various forms, - in its raw state, reeled as filatures, re-reels, and hanks, as cocoons, and waste-silk; manufactured, chiefly in the form of piece-goods and handkerchiefs. For some years there was also a large export of silkworms' eggs. Continental Europe and the United States are Japan's chief customers for raw and waste silk. Her manufactured silk finds a market all over the world.
Book recommended - Rein Industries of Japan, p. 378et seq.