How Kihachijo is Made Production by Traditional Methods

1. Sericulture

Raising silkworms and making cocoons

Silk is made from the cocoons created by the larvae of a moth called the silkworm moth. The process of raising silkworms by feeding them mulberry leaves to produce silk thread is called sericulture. Sericulture has been practiced on Hachijojima since ancient times because mulberry leaves grow wild on the island (sericulture is no longer practiced today).

2. Silk Reeling

Extracting the thread from the cocoon

The cocoon is held together by a substance (sericin) produced by the silkworm, making it very hard and difficult to unravel. Therefore, the cocoons are boiled in a pot to loosen the adhesion and make them easier to unravel. Since a silkworm creates its cocoon with a single thread, pulling on the unraveled part and winding it onto a spinning wheel produces one long thread. One cocoon can yield 1,200 to 1,500 meters of thread. This silk thread is very fine, so several strands are twisted together to make raw silk (raw silk is now sourced from outside the island).

3. Dyeing

Dyeing the thread with the island's plants

The colors of Kihachijo are only yellow, reddish yellow, and black, but the splendor of Kihachijo lies in this dyeing process, with the beauty of the yellow being particularly outstanding. The dyeing is done entirely without chemical dyes, using only plants native to the island. After repeating the "shita-zome" (under-dyeing) process of soaking the thread in a decoction of plants dozens of times, it is then soaked in wood lye or swamp mud to fix the color, and then dried in the sun. Thus, the dyeing of Kihachijo is a very time-consuming and laborious process.

4. Weaving

Weaving the cloth with three colors of thread

Kihachijo is a hand-woven silk fabric using a loom called a takahata, and is woven into striped or checkered patterns by combining three colors of thread: yellow, brown, and black. The takahata was introduced in the Meiji period, but before that, a traditional loom called a jibata, which was physically demanding, was used. There are two main weaving methods: plain weave and twill weave. Plain weave is the basic method of weaving where the warp and weft threads cross over each other one by one, but since Kihachijo thread is prone to showing imperfections, it requires skilled technique. Twill weave is a method where the points where the warp and weft threads cross form diagonal lines, and it is said that there used to be over 100 weaving techniques.

5. Finishing

Washing off the starch with hot water

Kihachijo is alkali mordanted, and the starch applied to the warp threads contains camellia oil, which oxidizes over many years and turns into fatty acids, causing the color to fade. Therefore, at the end, the fabric is soaked in hot water of about 40°C for about 30 minutes, and then the starch is washed off with a scrub brush under running water. This is the finishing process called "yudoshi."