-- "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.
The Korean Strait
An Isthmus
If the three main southern islands you are referring to are the Ryukyu Islands, including Okinawa, and the rest of Japan referring to the 4 main islands of Japan, then the answer is the East China Sea. If the three main southern islands you are referring to are Kyushu, Shikoku and Honshu, and the rest of Japan referring to Hokkaido, then the answer is the Tsugaru Strait.
It is Sea of Japan.
The body of water that separates the three main southern islands from the rest of Japan is the East China Sea.
tyboka sea
Korea is east of the Yellow Sea, which extends into the Korea Bay, and separates Korea from China to the west.
The Yellow Sea and East China Sea
Japan is separated from Asia by the Sea of Japan (also known as the East Sea).
Unless there is a practical reason why so many names have to be supplied to ONE body of water (the pacific ocean in this case), only the"Sakhalin" peninsula separates the "Sea of Okhotsk" from the Japan Sea. The Japan Sea is surrounded by Russia/Korea/Japan; to settle the dispute, it should be named for what it really is, the "Sea of Okhotsk."
That's "East Sea" a.k.a. "Sea of Japan".
The Korea Straight lies just above East China Sea, To the left of Japan, next to, slightly below South Korea. Pretty much the body of water that seperates the bottom of Japan and South Korea .