Canon

Whenever an author writes a series, everything he or she wrote themselves is considered canon. To put it more simply, canon is the original material that was stated by the writer in their work.

Manga
To know the story of One Piece and its content, you must look towards the Japanese print of the manga; where the series started from. The manga is the backbone of the One Piece materials, without it, One Piece wouldn't exist. Everything, everyone, any events or information found in the manga is canon.

Some filler characters are designed by Oda for Toei (anime) and Bandai (video games) that he never used for the main storyline.

Mini-Arcs
Mini-arcs are stories that is found on cover titles that was suppose to tell a story about what happened to minor characters that met the Straw Hat Pirates while the pirates are adventuring. Even if it was not the part of the main story, it is consired a canon since most of the stories would eventully connect to the main storyline

Databooks
The databooks gives out more detailed information on the manga, giving names not found in the manga but they are consired canon because Oda himself supplied these information.

Grand Line Times
This is a catch up review, giving out feedbacks that fans already knew about in the series, however it can be consired a canon. Oda written this a few weeks after he had fallen ill. After he recovered he decided to do this to help fans catch up with the series.

Anime
The anime can be highly canon if it's following the manga but sometimes the anime becomes independent and inserts it's own information that is not found in the manga. At other times, sometimes Toei can subtly foreshadow the events that is coming up in the manga (mostly due to events being done in the manga prior). For example, Toei showed a ghostly image of Going Merry during the Sea Train episodes, fans never understood this until Going Merry returned in the manga to help her crews escape before dying for good. Also after the Luffy vs Usopp duel, Toei has Zoro acted cold towards Usopp by telling Chopper not to talk about him (which is understandable given Chopper's want to support both sides despite the heavy emotions). Fans thought this move was out of his character but in the manga, Oda had Zoro acted the same way after Luffy learned that Usopp wanted to re-join but did not like the idea of Luffy being weak like that. It appears that Oda sometimes tell Toei what he was planning or giving out an hint but the anime is not always trustworthy. The anime was meant to describe the events in the manga, expanding the roles and actions to fill up the 30 minutes timeframe. They would add events, histories, information, extra scenes not found in the manga. But sometimes Oda did take examples from the fillers to add in his canon storyline.

Toei can even create a plothole, for example in the Warship arc, Zoro stated that there is nothing he can't cut which could be understood as a bluff by watchers, but the fact that he claimed that the chains he cut were steel is a major plothole as in the manga (and the anime), he was shown to be unable to cut steel until the Arabasta arc. In the Davy Back Fight, Chopper ate 3 rumble balls with no problem but in the manga, Chopper was not suppose to eat another rumble ball within 6 hours. In the Coby/Helmeppo filler, Garp, Coby and Helmeppo went up Reverse Mountain but in the manga they went through the Calm Belt, however Toei covered up the mistake by having Coby state that the newspaper was wrong.

As for the fillers, they were added to prevent the anime from catching up with the manga, during the filler arcs they often insert pieces of canon material in the middle of an filler episode, they often add in a child that is annoy to many fans and would end the filler arc with a canon story. Here are the list of filler arcs and filler episodes added by Toei. Take note that none of the fillers has any connections to the canon storyline.


 * Warship Island Arc: Takes place between the Loguetown arc and Reverse Mountain arc. In the manga, the Straw Hat Pirates were suppose to escape Loguetown, enter and escape the Calm Belt before going up Reverse Mountain without any interruptions, Luffy was suppose to save Usopp from the Sea King instead of Apis. During the Warship Island Arc, Oda had just wrapped up Drum Island and was doing the early chapters of the Arabasta arc.


 * Post-Arabasta arc: The arc was made up in 3 parts, the stand alone episodes (for each of the crew members but Luffy and Robin), Goat Island arc and Rainbow Mist arc. It took place after Nico Robin joined the crew. In the manga, after Robin joined, a ship fell from the sky. This filler was made because Oda was in the early stage of Skypiea.


 * G8 arc: The Straw Hat pirates landed in a bay of an Marine base. In the manga, they landed in an open water after Skypiea, Nami tries out the waver and Luffy would discuss about getting a shipwright. In the G8 arc, it was Usopp who discusses about getting a shipwright with a repairman.


 * Ocean's Dream Arc:


 * Ice Hunter arc:


 * Spa Island arc:

Novels
Twelve novels were written depicting various stories connected or separate from actual canon as depicted by Oda. The first novel is an expanded version of the Loguetown arc written by Tatsuya Hamazaki with ideas and concepts by Oda. One of the concepts used in the novel was a sequence left out of the manga explaining how Usopp received his goggles and his encounter with Daddy Masterson, which could be considered continuity or filler dependent on your views.

OVA
This is the first anime in a movie form created in 1998 one year before Toei took rights to create the series based on the manga. Only Luffy, Zoro and Nami are in it, since it was out when One Piece was in the Kuro arc, Usopp did not appear. Genzak, a villain with a armor with a crab claws was a basic concept for Don Krieg.

Cross Epoch
This crossover comic that featured the Dragon Ball cast and One Piece cast does not have anything to do with the main storyline, fans don't consider this a canon.

Video Games
Video Games may feature characters and events from the manga, they have nothing to do with the canon storyline.

Features
Toei intended to insert special features, they have nothing to do with canon.

Omake Features
Most of the comics Oda drew in the omake have nothing to do with the canon, despite the fact that Oda drew them. The comics often humorously featured the One Piece cast in different roles and different situations which are standalone stories. However, the only possible omake which possibly could occur in continuity is Report Time, which supposedly chronicles the Straw Hat crew's eating habits during the first parts of their voyage.

Movies
Movies 1-9 were supposed to take place during the series but they have few, if any, connections to the main storyline. Rather, these movies were based on the events of the series.


 * Movie 1 takes place in the East Blue, just before Sanji is introduced.


 * Movie 3 has Tony Tony Chopper in it, but can not occur in canon since neither Nefertari Vivi (who was there when he joined) nor Nico Robin (who joined the crew immediately after leaving Arabasta and Vivi) are in this.


 * Movie 4 took place after Arabasta, the confrontion between Gastpude and Luffy was similar to the confrontion between Crocodile and Luffy (Luffy screaming Gastpude's name like he did with Crocodile and coated his hands with powder to fight Gastpude like he uses blood to fight Crocodile)


 * Movie 5 took place while the series is in Skypiea, this movie has many Jaya/Skypiea elements. Amazon Lily is also inspired by the movie.
 * Movie 6 is similar to Davy Back Fight, only that the setting is darker, and the events bigger.


 * Movie 7 was supposed to take place before Water 7. Although there are machines in the movie, Oda later added Machine Island to the canon storyline, although the only mechanics on this island were the Spaceys created by Moonwatcher. While this movie is not to be consider canon, it shows Luffy activating Gear Second unwittingly, being a possible explanation for the origin of the technique.


 * Movie 8 was suppose to take place during Arabasta arc but many things has changed. Ace, Rainbase, the Marines, and Mr. 3 did not appear in the movie. It was different from the canon Arabasta


 * Movie 9 takes place in Drum, but Vivi is not in it, Robin and Franky make an appearance, and Wapol has an older brother and new subordinates. It is dramatically different from the canon events that occurred at Drum.

Fanon
For farther information, look here Fanfiction

Why Canon?
One Piece Encyclopedia editors must always write down information that was written in the manga only. This is to avoid confusion and to help readers know the full pure story of One Piece. For example, most Dragon Ball fansites always have information that is mostly from the anime. As a result, many people get confused on which is filler and which is not, once they read the manga they may not be sure if the anime started first or the manga. We do not want that here, we want to make a clear information on the One Piece story.

Which is why we must follow what's in the manga because Oda is the one who wrote the series, he is the one who make up rules and he's the one who drew the series.

If you create a page that is from the filler arc, one must put in the Category:Non-Canon. When a canon character has a filler alternation, one have to list them in the Anime/Manga difference section. Any rules or story made by Toei is not allowed to go in the canon information mainstream.