This place called Kosouen is one of a few studios that still keep dyeing in an authentic, traditional method. You’re going to dye a handkerchief by soaking and rubbing the cloth in a vat filled with indigo liquid. You can make your own and take it home as souvenir. There are showrooms in this studio where we can buy their original products.
Indigo is called “Ai” in Japanese that is deep blue color as you can see the picture below.