tyboka sea
Japan is separated from Asia by the Sea of Japan (also known as the East Sea).
The sea of Japan.
sea of Japan
The Sea of Japan (also known as the East Sea) separates Japan from Asia.
Japan is separated from mainland East Asia by the Korean Strait and Sea of Japan.
water
The Red Sea separates North Africa from Southwest Asia
If you are referring to seas, the Japan sea and the Pacific ocean are on either side of Japan. If you mean the body of water between Hokkaido and Honshu it is called the Tsugaru Strait.
The only body of water that makes any separation between the two is the Black Sea and the Bosporus.
The Atlantic Ocean
hollywood
The Pacific Ocean separates Asia and California, The Arctic Ocean separates Alaska from northern Asia.