Korea is east of the Yellow Sea, which extends into the Korea Bay, and separates Korea from China to the west.
Directly west of the Korean Peninsula, the body of water is called the West Sea. Imaginative right? Further west would bring you to the Yellow Sea, and then going north-west is the Bohai Sea
North Korea has borders with both China and Russia (at Khasan). The Korean peninsula is separated from mainland China by the Korea Bay (in the north) and the Yellow Sea. (see map link)
Yellow Sea, East China Sea, and the Sea of Japan
-- "The Yellow Sea"In response to the previous answer, the Yellow Sea separates The Korean Peninsula and Mainland China.The 'Sea of Japan' separates Japan from the Asian mainland (including the Korean Peninsula). The 'Korean Strait' also separates the southern coast of South Korea from Japan.Please see a labelled map in the related links below.
Yellow Sea, East China Sea, and the Sea of Japan
the adriatic sea
The Yellow Sea on its west side and the Sea of Japan on its east side are bodies of water between the Korean Peninsula and China.
The Spencer Gulf lies between Yorke Peninsula and Eyre Peninsula.
hollywood
The Korean Strait
Maybe that's Hong Kong harbour, it's part of the South China Sea