This theory isn’t really about what One Piece is as a treasure but what the actual words “One Piece” mean. I read an old interview of Oda’s and he said the words “One Piece” are important to the ending of the story.
I always thought One Piece was a really weird thing to call treasure. I’m like is it a code word or something? But the answer I came to is much simpler. While thinking about what it could mean I remembered that piece means coin. We say 50 cent piece. But One Coin doesn’t sound like much of a treasure. Then I remembered the nine pieces of eight in Pirates of the Caribbean. So I googled piece of eight coin and not only are they heavily related to piracy but they look like this:
Which looked familiar to me. A circle with a cross in the centre:
And apparently people used to cut the coins up to use as individual currency.
Take note of the one cut into 4 in particular.
There’s a good chance you already know the theory that One Piece will end with the destruction of Reverse Mountain and Marijois and All Blue will form where the 4 oceans meet.
My theory is the oceans were originally one ocean to begin with and the World Nobles divided them to make the world easier to rule. I think One Piece is the knowledge and means to remove the barricades aka the Red Line and the Grand Line and return the world to its original state. Probably not original, I know.
And the reason it’s called One Piece? It’s a metaphor. I can see how someone could think that a piece of eight coin or eight piece put back together would be a one piece. And 4 Blues put back together would be an All Blue. I think it fits too as a reference to coins and pirate treasure. One Piece is supposed to be the ultimate treasure and while one coin isn’t much, the means to take back the whole world is pretty valuable.
Well that’s it. Let me know what you think.
*Theory by Hithere