A long time ago, Tokushima was a big-time indigo producer. Athough natural indigo dyes have largely been supplanted by synthetic dyes, there are a few diehard (pun intended) farmers growing the stuff, and indigo-dyed products are sold in every local souvenir shop.
This year, the students at my daughter’s school are involved in an indigo project. They started in the spring, when they planted indigo seeds and tended the sprouts. By summer, the leaves were big enough to harvest. They were dried out on tarp. Now the leaves are fermenting in water in a big vat. The kids take turns stirring the stinky, goopy brew. When the mixture is ready, they will dye handkerchiefs.