Oku means “depth / inner space” in this Miroshaki Aquascaping Dictionary. A sense of inner depth or background distance. It helps describe where things sit in the layout and how the eye moves through the aquarium.
Japanese: 奥 Romaji: Oku
Meaning of Oku
Oku is explained here in simple English so beginners can use the word without feeling lost. In Miroshaki style, the term is not only a translation. It is a small way to look more carefully at nature underwater.
How Oku Helps in Aquascaping
Use it to make a small tank feel larger and more layered. This can help when you choose stones, place wood, create open space, plant moss, or wait for the aquarium to grow into a more natural balance.