The islands are Japanese.

I said Sout Korea in my comment what are you talking about?

and who is the only country that really support North Korea?

As for vietnam.  It's funny.  The government is communist and tied to China after the fall of the USSR, but the everyday people kind of hate china, due to the Sino-Vietnamese war of 1979 where the chinese practiced scorched earth policies razing many of the places they invaded.

Hell I actually think the borders between the two countries are still heavily militarized.

They actually have strated increasing their military funding in response to the Chinese plans for expansion.

Korea, Vietnam and the rest of the "Little" countries, don't much like either China or Japan... seeing them both as the regional bullies.

As I said, I wonder why South Korea should fed up with China, as South Korea is more in trouble with Japan and North Korea as with China.

China influences North Korea usually towards less confrontation, therefore South Korea is usually happy about the influence. True enough, without China North Korea wouldn't last.

I'm aware about the war between China and Vietnam, that's why I said possible. But I didn't read about any current problems between the two.

And yes, China and Japan are the regional bullies and not much liked by the other asian countries.

To the topic itself: All three countries have a very weak claim to the islands and all three didn't bother until the resources in the sea were discovered. Since then the governments use the patriotic feelings in all three countries that claim these island to strengthen their claim.