万緑叢中紅一点

Etymology
Borrowed from. Compare Chinese. Both are derived from a line in Ode to a Pomegranate Flower (咏石榴花) by Wang Anshi:

Idiom

 * 1)  a beautiful single red flower that blooms within a field of trees and grass
 * 2)  something unique that stands out among many other things
 * 3)  a single woman among many men