Which japanese drama has the highest rating in history?

Question:

5 pts for explainable answer:)

and if you can also give me the highest ratings of korean and taiwan dramas too
that would be great.
thank you

Answer:

The Japanese drama Oshin is regarded as being one of the highest rated Japanese drama in history. The show has been aired all around the world.

http://en.wikipedia.org/wiki/Oshin