"シカク" means eyesight in Japanese. It's written like 視覚 in KANJI. At the same time, シカク has another meaning in same pronounce.
It's written like 死角. And it means blind angle in Japanese.
These two meaning in a same pronounce are coincident anytime. When I gain something, I lose something at the same time.
But I can't be aware of it consciously without time elapse.