Canon

Canon (not to be confused with  can(n)on) is a term used to designate what is considered "official" in a certain fictional universe. Unless otherwise specified in the  OP, only canon material can be used in a debate thread. Non-canon material doesn't count - it never happened.

Many debates have been held on exactly what is and is not canon.

The generally agreed-upon definition is that the work by the original author and creator of the fictional setting is canon, unless the author or the copyright holder declares otherwise.

So for most manga series, that means the original manga is canon, while the anime is not (since the anime is simply an adaptation of the manga made by others). Databooks are considered secondary canon since scans tend to contradict them or the writer is a moron ( Haku is  FTL...) It should be noted that this is often evaluated on a case - by - case basis.  A  notable exception is the  Tenchi Muyo! series, where the OVAs are canon since they are the original work of the author, and the manga is written by a completely different person and is not canon.

Major canon debates that have occurred in the OBD:

1. Dragon Ball. Despite the overwhelming  view<span style="color:rgb(51,51,51);font-weight:normal;"> that the manga (and now,  Dragon Ball Super<span style="color:rgb(51,51,51);font-weight:normal;">) is the only canon, many people (specifically the  Phenom Brigade<span style="color:rgb(51,51,51);font-weight:normal;">), have attempted in the past to claim that the anime,  movies<span style="color:rgb(51,51,51);font-weight:normal;">, and  GT<span style="color:rgb(51,51,51);font-weight:normal;"> are canon. The movies are obviously non - canon, since they fit nowhere in the timeline (Movie 9 is debatable <span style="color:rgb(51,51,51);font-weight:normal;font-family:Arial;">) <span style="color:rgb(51,51,51);font-weight:normal;">. GT was made after Toriyama quit, and was created by different people with no basis on the manga. Also, there were many irreconcilable contradictions with the manga, so it is generally considered to be non - canon.

<span style="color:rgb(51,51,51);font-weight:normal;">The anime is sometimes argued to be canon, usually by using various  Toriyama<span style="color:rgb(51,51,51);font-weight:normal;"> interviews. However, none of these interviews actually state the anime is canon, just that Toriyama contributed some character designs for GT and the filler anime. In fact, they often provide evidence that it is not canon, by explaining how Toriyama would just let the animation studio do whatever they wanted after giving them a rough outline, or pointing out that there were many differences between the anime and the manga.

<span style="color:rgb(51,51,51);font-weight:normal;">The recent TV special "Yo! Son Goku and his Friends Return!" has been argued to be canon, because it was written directly by Toriyama. However, there is little in it that is usable for debate purposes, so there have not been many major  arguments<span style="color:rgb(51,51,51);font-weight:normal;"> over it.

<span style="color:rgb(51,51,51);font-weight:normal;">Recently, it has been argued that the backstory of the upcoming MMORPG  Dragonball Online<span style="color:rgb(51,51,51);font-weight:normal;"> is canon, due to Toriyama's involvement. This is still disputed. A similar claim is being made about a recent spin off manga about  Bardock<span style="color:rgb(51,51,51);font-weight:normal;">. Adding to the confusion, it has been argued that due to the nature of time travel in Dragon Ball, most of the Bardock spinoff would technically take place in an alternate time line, much like  Future Trunks<span style="color:rgb(51,51,51);font-weight:normal;">.

<span style="color:rgb(51,51,51);font-weight:normal;">2. Star Wars<span style="color:rgb(51,51,51);font-weight:normal;">. The Star Wars Expanded Universe used to be canon, based on George Lucas' subordinate Leeland Chee, who developed the "canon holocron" which explained the different levels of canon. However, with the purchase of the franchise by Disney, the EU was purged and made into a separate, non-canon  Legends<span style="color:rgb(51,51,51);font-weight:normal;"> timeline.

<span style="color:rgb(51,51,51);font-weight:normal;">3. Neon Genesis Evangelion<span style="color:rgb(51,51,51);font-weight:normal;">. A large number of secondary sources, some of which seem to be contradictory, say that the anime is canon since it is the original work of Anno. While the manga was done by a different author; Anno stated that the Manga is its own canonicity and the Manga can be used to support the anime when they are in explicit agreement; while the Rebuild of Evangelion series classifies as a wholly separate continuity with its own backstory, which may not be applicable to the TV series and shall be treated as such. Their also the deleted scenes that appear in the director's cut episodes but they are often not counted as canon since they where removed on final or official versions and take precedence over the TV version in the event of any theoretical contradiction.

<span style="color:rgb(51,51,51);font-weight:normal;">4. Transformers<span style="color:rgb(51,51,51);font-weight:normal;">. Everything is canon. <span style="color:rgb(51,51,51);font-weight:normal;">In  Transformers<span style="color:rgb(51,51,51);font-weight:normal;">, "canon" is for all intents and purposes a synonym for "official". If it was released by a  Transformers<span style="color:rgb(51,51,51);font-weight:normal;">  <span class="new" style="color:rgb(51,51,51);font-weight:normal;">licenser <span style="color:rgb(51,51,51);font-weight:normal;"> with Hasbro approval, then it is canonical. However, simply being canonical doesn't say anything about what continuity or continuities it applies to.

<span style="color:rgb(51,51,51);font-weight:normal;">3H and IDW have both released comics which take place "just offscreen" during the  Beast Wars<span style="color:rgb(51,51,51);font-weight:normal;"> cartoon, but these comics contradict each other. Rather than the newer IDW comics  invalidating<span style="color:rgb(51,51,51);font-weight:normal;"> the 3H story or  retconning<span style="color:rgb(51,51,51);font-weight:normal;"> it out of existence, the two are simply relegated to separate but closely parallel  universes<span style="color:rgb(51,51,51);font-weight:normal;">. While this " multiverse<span style="color:rgb(51,51,51);font-weight:normal;">" approach helps to ensure that essentially all  Transformers<span style="color:rgb(51,51,51);font-weight:normal;"> fiction is given a certain amount of validity, there are occasions when individual texts within the same continuity contradict each other. (The history of the Constructicons in the original cartoon series is probably the most infamous example.) When this happens, there is no clear way to proceed. Fans may reach a consensus on how to best interpret the evidence, but this consensus is  not official<span style="color:rgb(51,51,51);font-weight:normal;"> and therefore not canon. (Until/unless somebody writing official fiction drops it in, transforming it from fanon to canon.) Each fan's interpretation of such events constitutes a part of their personal canon, a subjective collection of ideas about the official fiction which is typically a work in progress that is constantly being reevaluated.

<span style="color:rgb(51,51,51);font-weight:normal;">5. Doctor Who<span style="color:rgb(51,51,51);font-weight:normal;">. Much like Star Wars, there is a canon hierarchy, although it is not as official. The primary canon consists of:

<span style="color:rgb(51,51,51);font-weight:normal;">- The main Doctor Who television series (including the Christmas specials and other special episodes that tie into the main plot, including most of the recent Comic Relief specials) <span style="color:rgb(51,51,51);font-weight:normal;">-  The 1996 TV movie <span style="color:rgb(51,51,51);font-weight:normal;">- The spinoff series Sarah Jane Adventures, Torchwood, and K9, as well as the K9 and Company pilot (ugh...)

<span style="color:rgb(51,51,51);font-weight:normal;">The secondary canon consists of most other licensed media, including novels, comic books, video games, etc.