Defined as "extremely deep blue" in the JIS standard. A deep indigo blue. Some describe it as falling between indigo and navy blue (#192f60), slightly brighter than navy. The difference is barely noticeable unless placed side by side. Similar colors appear in the ancient Engishiki code, attesting to its long history. Indigo and navy, along with brown and gray, were among the most popular colors of the Edo period, spawning an extraordinarily rich palette.