꿩 먹고 알 먹고 (Kkwong meokgo al meokgo)

Literally: Eating the pheasant and its egg too

Example: “자전거로 출근하면 운동도 하고 돈도 아끼니 꿩 먹고 알 먹고다.” — Cycling to work gets me exercise and saves money: two birds with one stone.

English equivalent: To kill two birds with one stone

Origin: No clearly documented first use survives, though the phrase is understood to be old and long-circulating in ordinary speech. The logic draws on real pheasant behavior: an adult pheasant is normally sharp-eared and quick to fly off at the first sound of an approaching person, but a hen pheasant sitting on her own eggs is driven by such strong maternal instinct that she'll often stay put on the nest even as danger closes in, unwilling to abandon what she's protecting. Someone who found a nesting hen pheasant this way could walk away with both the bird itself and its eggs in a single stroke — one small, real hunting scenario that gave the idiom its lasting image for getting two separate benefits out of a single action.