Thanks Robin. Of course you are right but I needed a literal translation so that it made sense for the article!
Thanks Graham. I didn't know that about Greek.
Thanks Daian. It's always good to hear your stories. The indigo hakama are beautifully made articles of clothing. But they are not practical for suwari waza in the heat of Japan.
A couple of other points about blue and indigo.
I noticed there is a drink called indigo.
I didn't mention that blue 青い aoi is used in Japanese to mean pale-faced or wan.
Carina suggested talking about blue jeans. Jeans are dyed with indigo. The word jeans comes from bleu de Gźnes - Genoa blue. And the word denim comes from fabrique de Nīmes - denim fabric.