Shii trees are chipped, boiled, and left to rest for 3–4 days to extract the dye.
After dyeing with this extract, the color is fixed by repeatedly dyeing in a mud field.
This entire process is repeated a total of four times to create a deep, rich color.
Shii trees, known as "Sudajii" on Amami Oshima, are a central plant in the island's ecosystem, growing wild in approximately 80% of its forests.
At the workshop, only the necessary amount is carefully harvested from nearby mountains for each dyeing process, ensuring consideration for the natural environment.