the korea bay, sometimes the west korea bay (; or ), is a bight and the northern extension of the yellow sea, between the southeastern coastline of china's liaoning province and the western coastline of north korea's north pyongan, south pyongan and south hwanghae provinces. it is separated from the bohai sea by the liaodong peninsula, with dalian's lüshunkou district marking its western end, and westernmost tip of north korea's ryongyon county as its eastern end.