The body of water that separates the three main southern islands from the rest of Japan is the East China Sea.
Sea of Japan
The Arctic Ocean
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.
Japan, Malaysia, Indonesia
The North Sea separates Britain from the mainland of Europe. Britain is an island that has three countries on, which are England, Wales and Scotland. Only England and Scotland have a North Sea coastline.
the 3 island chains east of china are Taiwan( to Taiwan!), Japan, and Philippines
Japan is an archipelago, meaning that it is a string of islands. And the small landmass of Korea is a peninsula of the Asian continent, meaning it's surrounded by water on all three sides. Therfore, it is not a channel that separates the two countries, but the ocean itself.
hokkaido honshu kyushu
Three island countries of Asia are Indonesia, Philippines, and Japan.
Hokkaido, Koshuku, and Honshu
Its in the southern western sea South of molida island you will find three boulders. The island is between those boulders.
Great britian
Polynesia, Melanesia, and Micronesia are the three major island groups of the Oceania region. These island groups are located in the central and southern parts of the Pacific Ocean.
Honshu The largest island of Japan is Honshu