Tomoo Inaba
Dying out of Purple
 
Since ancient, purple pigments have been extracted from plant roots named Shikon (紫根). It's very difficult to cultivate, and nowadays it's one of the very rare natural materials. Surprisingly, I found after I moved from Tokyo to the countryside in Oita Prefecture ten years ago that it's still cultivated here in small quantities.
It's similar to beetroot, which has a deep reddish-purple color but turns gray if boiled for too long. So I came up with the idea that the color is likened to the famous L'Heure Bleue by Guerlain, and created the purple hour between the blue hour and midnight.