Yu-Gi-Oh! (Toei anime)

The first Yu-Gi-Oh! anime series (also known as Season 0) was an anime Series created by Toei Animated based on the first 7 chapters of the YuGiOh manga. It tells the story from a time before the card game had any importance, and a little bit afterwards.

It was eventually replaced by the second anime series, which preferred to skip all the first parts of the manga in favor of focusing only on the card Game arcs. Nevertheless, the second series does make some nods to this one which can only be fully understood if you've watched it.

The second anime series explains very little of this series' plots, with a good reason: before Duel Monsters entered in, this series was completely different, bordering more a G-Rated Saw than Yu-Gi-Oh. For this reason, both series can complement quite well without feeling you are watching the same thing twice (at least, until it gets to the card games).

It's also worth noticing that many things created by this series were later used as inspiration for later chapters, like the more common presence of Seto Kaiba as a villain. It's also worth noticing that this incarnation of Seto Kaiba is what inspired Noa(h), the Big Bad from the third series of the second anime.

It spawned a 30 minutes OVA, a few video games and a card game created by Bandai, (which would later be replaced as well by the newer card game).

Little Kuriboh did some episodes of an Abridged Series of this series as well.

Tropes used in Yu-Gi-Oh! (Toei anime) include:

Abandoned Warehouse: The Toei Yu-Gi-Oh! series gave a warehouse to the yoyo gang, the Capumon guy and the guy who plays with 'digital pets'.
Abusive Parents: Jounouchi's alcoholic father, as well as Seto and Mokuba Kaiba's stepfather.
Adaptational Villainy: It's hard to imagine Seto Kaiba being any more evil than he was in the manga's Death T arc, but at least there it was shown that his stepfather Gozaburo demonstrating to him that "to lose is to die" via his suicide and his later experiencing an illusionary death as penalty for losing a duel to Yami Yugi gave him a solid Freudian Excuse. In this anime, the "experience death" penalty game doesn't happen, and Seto taking over his company from Gozaburo happens in the present day time while Seto's still an evil sociopath, which leads Gozaburo to a botched suicide (he gets vertigo and faints rather than jumps out the window) which has no effect on Seto whatsoever.
Adaptation Dye Job: Seto Kaiba....has GREEN HAIR.
Amusement Park Of Doom: Death-T.
Ascended Extra: Miho Nosaka.
- To elaborate, she was only used in one chapter in the manga as a love interest to Tristan (who promptly shot him down when he asked to be her boyfriend). She was used more in the anime to help fill out the girl quota though at best she mostly a Satellite Character. Yu-Gi-Oh! Abridged (when it focuses on the Season 0 series) hilariously lampshades this by hardly having her speak and when she does it a very over the top voice that the other characters bluntly ignore.
- Also Seto Kaiba. At the time of this anime's production, he was an Arc Villain, but this anime made him the recurring Big Bad.
Ax Crazy: Yami Yugi can become Axe Crazy if you get him mad enough.
Believing Their Own Lies: An early Phony Psychic enemy of the week.
Beware the Nice Ones: Ryou Bakura is a very sweet, shy, quiet, polite guy. With a Super-Powered Evil Side that he's only vaguely aware exists.
- The same goes for Yugi. He is nice and weak, until his psychotic side wakes up.
Big Bad: Seto Kaiba, by virtue of being the Arch Enemy, is this for most of the series, with Yami Bakura taking over the role for the last few episodes.
- Bigger Bad: Gozaburo Kaiba, Seto's abusive stepfather, who shows up in person only once in the show.
Bitch in Sheep's Clothing: Seto Kaiba, he pretends to befriend Yugi and has Yugi's grandfather's Blue Eyes White Dragon switched with a copy. When Yugi figures this out and calls out Kaiba on the switch, Kaiba loses the facade and whacks Yugi in the face with a briefcase.
Character Development: Mostly for the two Yugis, but everyone gets a decent amount at the least.
Clothes Make the Superman: Cruelly averted in the Zombire story.
Collectible Cloney Babies: Capsule Monsters, Capmon for short. They would come from a vending machine, with the luck of the draw determining what monster level and type you get. Part of the fun is the randomness, and that you use these monsters to battle. Someone gifts Miho a Gacha box loaded with Capsule Monsters. The capsules are filled with jewels, and Miho reveals a university student, an avid Capmon collector named Warashibe-kun, was hitting on her. Yugi happens to know him, and catches up with Warashibe-kun after school to ask him about it. Miho isn't impressed with the CapMon she sees, saying they aren't that cute for collecting, and gets creeped out when Warashibe stages a meeting with her, calling her his "Capmon Queen". Yugi beats him in a Capmon duel when he poisons Anzu, Honda and Jounouchi and blackmails Miho.
Color Wash: The first anime has an incredibly supersaturated neon palette.
Conspicuous CGI: The first series had this a few times (such as in the opening, or in episode 6 with the stairs) and it was quite obvious.
Cooking Duel: Figuratively speaking. The series often stakes the lives of its characters, or even the fate of the world, on a game of Duel Monsters.
Cosmic Role-Playing Game: Season 5
Covert Pervert: Yugi—he is shown imagining someone's panties after hearing what Tea has to say about boys peeking up girls' skirts while playing basketball. Even in the Millennium World Arc they're still exchanging videos... Manga link
The Corruption: Multiple instances with various characters. The entire Doma arc works on this.
The Dark Side: Many characters in Yu-Gi-Oh! fall into some Dark Side's trap, usually by trying to use an Artifact of Doom (e.g., Marik, Bakura, Pegasus, Aknadin). Yami Yugi is not immune to this effect.
Darker and Edgier: than the later anime series
Death Trap: Kaiba's sadistic "amusement park," "Death-T," is basically a long series of increasingly difficult death traps designed to defeat and kill Yugi.
The Ditz: Miho Nosaka.
Duels Decide Everything: If you have a conflict, battle with cards!
Fan Nickname: 'Series 0' or 'Season 0' for the Toei anime.
- The Forbidden Season
Fighting Series: Using a children's card game.
Early Installment Weirdness: A dark series about a weak and pathethic boy whose darker side wakes up to brutally punish those who inflicted pain to him by using demonic magic (which requires a victory in an unspecific game to activate) ... it totally sounds like a series about a children's card game.
Irony: This series ended after adapting the manga's third story arc, prior to when the card game would completely take over the franchise, meaning that it ended at a Tabletop RPG with Yami Bakura and a demonic monster called Zorc that he was controlling as the Final Boss. It turns out that this would also be true of the manga and second anime.
Karma Houdini: The Hekate sisters, a trio of teenage witches in one episode, go completely unpunished for their crimes aside from getting defeated in a duel by Kaiba's intervention, as the episode just abruptly ends after Kaiba walks out the door.
Too Dumb to Live: Kaoruko Himekoji, the Alpha Bitch antagonist of one episode, gets her comeuppance not from any Mind Rape or penalty game, but by Yami Yugi telling her the shocking truth that people grow old and lose their good looks to age! Hearing this makes Kaoruko lose heart in her act for the talent show and she basically sleepwalks through it as a result.