Canon

Canon

What is Canon
When you write a series and everything you wrote is considered canon, canon is the original material that was stated by the writer.

One Piece Canon
What is One Piece canon? To know the story of One Piece and it's content, you must look towards the manga; where the series started from. The manga is the backbone of the One Piece materials, without it, One Piece don't exist.

The movies, the t.v. specials, video games, and anime fillers are non-canon. Olny what's stated in the manga is canon

Say, in the manga; Vivi was the princess of Alabasta, that's canon because that is how the writer stated it. If you say that Vivi was a martian queen, that's consired [Fanon]] because Eiichiro Oda did not write Vivi to be an martian queen.

In the manga, Ace met with Luffy and his crews briefly in Alabasta, Ace left after destroying the Billion's ship. But if you have Ace follow the Straw-Hat pirates to Yuba then it's Filler.

History
In 1997, Eiichiro Oda started the manga series. In 1998 the One Piece OVA Defeat Genzack was released. In 1999 Toei created the anime that is based on the manga but since Toei often add their own plots or skipped parts in the manga. T.v. Specials and the movies was released, along with music.