keen eye; sharp insight
Refers to the ability to perceive things clearly and accurately; often used to describe someone's discerning judgment or perceptiveness.
With his keen insight, he immediately grasped the essence of the problem.
That art critic has a sharp eye.
Standard kanji spelling for this word.
From Chinese 慧眼 (huìyǎn), literally 'wisdom eye'. In Buddhist contexts, it refers to one of the five types of vision, the ability to see the true nature of all things. In modern Japanese, it is used more broadly to mean keen insight or sharp perception.