What are the 9 mountains and 8 seas?


So we have all seen Zoro boast.

> Over the 9 mountains and 8 seas... Throughout the world itself... There is
> nothing I cannot cut.

Now it made me wonder, which mountains and what seas was he referring to?




Some of Zoro's attacks are named after Buddhism like 36/72/108 Pondo Hou

[One Piece Wiki](http://onepiece.wikia.com/wiki/Roronoa_Zoro/Misc.):

> the 36/72/108 Pondo Hou, is a reference to the 36 passions of Buddhism

So most likely Zoro is referring to the Buddhist legend of
[Sumeru](http://en.wikipedia.org/wiki/Sumeru) the central world-mountain in
Buddhist cosmology.

I'm not an Buddhism expert but in the Wikipedia article about
[Sumeru](http://en.wikipedia.org/wiki/Sumeru) you see a list of 9 mountains
and 8 seas, so since Zoro likes Buddhism and Hindu references in his attacks,
it's most like Oda made a reference to this.

