Farmers in Yonezawa cultivated ramie and safflower plants during the early Edo period. In 1601, Kagekatsu UESUGI, the lord of the Yonezawa domain (modern day Yamagata), encouraged his subjects to cultivate them as exclusive products of the region. They were shipped to Echigo (now Niigata) and other regions as raw material for producing fabric. In 1776, Yozan UESUGI (ninth lord of the Yonezawa domain) started inviting artisans from Echigo to help with starting a fabric production industry by teaching weaving techniques to the local women.
At first, the textile was produced from ramie but the reformation of the domain encouraged more sericulture, and production gradually shifted to silk fabrics. Furthermore, in the Meiji period (1868-1912), silk fabric production spread to the nearby regions of Hakutaka and Nagai, which also had a successful silk industry. The advanced technique of making kasuri patterns was introduced and taught in these regions. Yoneryu kasuri and Itajime kogasuri became well known throughout Japan between the Taisho period (1912-1926) and the early Showa period (1926-1989). From 1976, the three regions unified their fabric production and the techniques of Kusakizome from Yonezawa, Yokoso kasuri and Tateyoko Heiyo kasuri from Nagai, and Itajime kogasuri from Hakutaka have been known as Oitama tsumugi.

1. Natural plant dyeing method (Yonezawa tsumugi kusakizome)
2. 1. Picking safflowers Safflower, which is similir to thistle, blooms bright yellow flowers in the summertime. Between the beginning and middle of July, however, the flowers become reddish and are picked in the early morning when the thorns have been softened by the morning dew.
3. 2. Kneading in water The safflower petals change their color from yellow to orange when they are kneaded in water. The yellow pigment dissolves and is easily isolated in water, while the red pigment is not as water-soluble and tends to remain in the petals.
   
4. 3. Fermentation Drying and fermenting the petals increases the red pigment by about ten times, and crushing them in a mortar and pestle intensifies the color even more.
   
5. 4. Producing safflower cakes The safflower petals are pounded to make flat safflower cakes, which are dried for ease of transportation and dye adjustment to control the depth of color.
   
6. 5. Dissolving of pigment and dyeing The safflower cakes are soaked in lye to dissolve the pigment. Threads are dyed an orange color, which changes to bright red after acid is applied. This step is repeated until the desired shade is attained.
   
7. Wooden board resist dyeing method (Itajime kogasuri)
8. 1. Reeling silk from cocoons The warp (perpendicular) threads and the weft (parallel) threads are prepared by teasing out fibers from the boiled cocoons and hand winding them to give the threads a natural texture.
   
9. 2. Winding the threads around a special board For the Itajime dying method, the warp and weft threads are wound around special boards with fine grooves carved in accordance with Kasuri patterns. Any discrepancy in the tension of the threads will affect the positioning of the patterns so this is an important process that demands great care and concentration.
   
10. 3. Dying the threads About ten boards with wound threads are stacked one on top of the other and temporarily tightened on the top and the bottom. Hot water is poured over the boards to fuse the boards and threads, then natural dye is poured over them. When the boards are removed, the threads are will have been dyed with the same patterns as the grooves on the boards.
    
11. 4. Weaving The dyed threads are left to dry and then woven by adjusting the threads so the patterns on the warp and weft threads are in their correct positions. Weaving requires great concentration as even a skilled weaver cannot weave more than thirty centimeters a day. This precise and detailed work produces the delicate patterns of Itajime kasuri.