The House of Indigo, also known as Ai no Yakata, sits in Aizumi, the old centre of Awa indigo production just west of Tokushima. The compound explains how the deep blue dye was grown, fermented, traded, and used in textiles before synthetic dyes took over.
It is strongest if you are interested in crafts rather than big monuments. Visitors can usually see dyeing tools and try a hands-on indigo workshop, which makes it a good half-day pairing with Tokushima's dance and castle sights.