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.
National pride./ Korean called the sea 'East Sea' since 414 (or before). But, Japan called the sea 'The Sea of Japan' since 1602(But they still used 'East Sea' more. And Japan decided to call the sea 'The Sea of Japan' in international conference, 1912(at that time, Korea was colony of Japan). And now, two country argue about that(and Korean tries to call the sea 'East Sea'). In fact, 'The sea of Japan' is wrong name cause the sea is between Korea and Japan-and Korea is not Japan anymore!
The Taiwan Strait is the passageway of water that connects the East China Sea and the South China Sea. It separates Taiwan from mainland China.
A buffer zone can refer to a designated area that separates conflicting parties to reduce tensions, such as the demilitarized zone (DMZ) between North and South Korea. Another example is a natural buffer zone, like wetlands surrounding a lake, which helps filter pollutants and protect water quality.
In Japan is surrounded by water and Korean is also surrounded by water and making there home (near the water) flooded from the earthquake (under the island and peninsula) make the wave get bigger than little wave.
In total, Japan's territory is 377,835 km², of which 374,744 km² is land and 3,091 km² water. This makes Japan's total area slightly smaller than the U.S. state of Montana. Japan is bigger than Germany, Malaysia, New Zealand and the U.K., and is 1.7 times the size of North and South Korea combined and 10 times the size of Taiwan.
The Korean Strait
-- "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.
It is Sea of Japan.
The only country that borders South Korea is North Korea. South Korea is also very close to Japan and China over the water.
Japan's neighbouring countries consist of North Korea, South Korea, and China.
North Korea is the only country that has a land border with South Korea. However, South Korea is not that far from China and Japan over the water.
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 .
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."
i believe the best awnser would be North Korea....
That's "East Sea" a.k.a. "Sea of Japan".
The Yellow sea and the Sea of Japan
Japan has no bordering countries since it is made of islands. The five closest countries to Japan are (in order) Russia, South Korea, North Korea, China, and Taiwan. North and South Korea, Russia and China.