Silkworms

Insects of the order Lepidoptera, Bombyx mori. Silkworms are insects that metamorphose gradually from eggs and are characterized by making cocoons when pupae. In order to obtain raw silk from the cocoons, they are bred with cultivated mulberry leaves. The history of sericulture (rearing of silkworms) is old. In Japan, simple silk fabrics from the middle Yayoi era of Kitakyushu have been discovered from the remains, and it is said that the practice came from China during the first to third centuries.

When the Taiho Ritsuryo (Taiho code) was enacted in 701, silk began to contribute to the country under the Soyocho tax system. Knowledge of sericulture began to spread to various other parts of the country from the Kinki region.

During the Edo era, the Shogunate and Daimyo (feudal lords) encouraged the practice of sericulture, and it became popular in various areas. The opening of the port in 1859 allowed raw silk exports and led to the development of the sericulture industry, which reached its peak during the Meiji era. In 1872, a government-run Tomioka Silk Mill was constructed in Gunma Prefecture. Machined silk was used.

After World War I (1914-18), Japan's sericulture and raw yarn production, which had continued to flourish as a major exporter to the United States, started to decline when it was hit by the Great Depression (1929) and then rising imports from overseas. 

For farmers, sericulture is a valuable source of cash income. As such, every January 15 cocoon-shaped rice cakes are laid on a wooden branch to pray to the guardian god of Kokage Shrine.