A counterfeit card is a fake trading card. Most counterfeit cards in the context of Yu-Gi-Oh! are made to mimic those of OCG or TCG cards. Counterfeit cards are usually made with the sole purpose of selling them as authentic cards to make a profit, which distinguishes them from fanmade cards, which may be sold as art, but not as genuine cards.
Many counterfeit cards can be easily recognized by flaws such as oddly colored or low-quality card backings or artworks, poor grammar in card names, effects, and other card text, and may use the wrong font or be incorrectly sized.
- Incorrect formatting, such as Levels/Ranks and ATK/DEF values on Spell and Trap Cards.
- Reversed Konami logo or incorrect spelling of "Konami" (e.g. "Konaini") or no Konami logo at all.
- Incorrect text fonts and/or mistranslated text.
- Incorrect card name, effect, Level, border, artwork, or ATK/DEF.
- The use of (often mistranslated) OCG names or artworks on what supposedly is a TCG card.
- Attributes without kanji, or nonexistent Attributes, such as "Sound", "Devil", or "Land".
- Incorrect ordering of card type. On a Monster Card the Type is listed first, followed by any Ability, e.g. "Machine/Effect", "Spellcaster/Spirit/Effect", or "Warrior/Synchro/Effect".
- Brightly or incorrectly colored card artworks, card backing, Levels/Ranks or card borders.
- Poor print quality (e.g. faded card artworks).
- Diagonal Secret Rare-esque lines printed onto a non-holofoil artwork.
- Common mistakes with the Type include: "Machine" written as "Maching", "Warrior" as "Fighter", "Zombie" as "Undeat", "Fiend" as "Insect", "Dinosaur" as "Dragon", and "Fairy" as "Angel".
- Card types which feature the type and sub-type being separated by a period rather than a slash (e.g. "Warrior.Effect").
- Fusion Monsters which list "Melting", "Amalgamation", "Mix" or "Combination" rather than "Fusion" in the type. Likewise, Ritual Monsters which list "Ceremony" instead of "Ritual". Synchro Monsters are often called "Homogenity" or "Homogeneous". Tuner monsters are often called "Adjuster" or "Adjusted". Gemini Monsters are often called "resummon".
- Incorrect terminology in card descriptions (e.g. using "Adversary"/"Rival" instead of "Opponent", "Life score" instead of "Life Points", "fieldside positioned" instead of "face-up", "Common Monster" instead of "Normal Monster" and "bout" instead of "Phase").
- Passcode/Limitation Text missing from the lower left corner. However some cards such as "Labyrinth Wall" do not possess a passcode.
- Copyright text (©1996 KAZUKI TAKAHASHI) missing from the lower right corner next to the Eye of Anubis Hologram or misspelled.
- "Kazuki Takahashi" spelled incorrectly (often due to being mistranslated).
- Spiral/circular reflective foil patterns over the entire card.
- No label indicating the language on top of the booster pack.
- Cards printed in a language that has not yet been officially released (such as Arabic).
- No Eye of Anubis Hologram, or the hologram is not reflective (however OCG cards with the original layout all lacked the hologram). The hologram is printed on genuine cards; if the hologram can be peeled off, it is a sticker and counterfeit.
- Incorrect Eye of Anubis Hologram, e.g. a supposedly 1st Edition card with a silver hologram instead of a gold one.
- Incorrect Rarity (most counterfeit cards are Common) or cards that is not holofoil with a holofoil colored card name (e.g. a card with gold lettering that is not reflective).
- Mismatched or incorrect logos, such as "New Yu-Gi-Oh!" or both "Yu-Gi-Oh! GX" and "Yu-Gi-Oh! 5D's" logos on the same product.
- On booster packs and boxes, the Cover Card does not match the set, or the set name given does not match any officially released set.
- On a character's Starter or Structure Deck, the featured cover card is not related to the character (e.g. "Cloudian - Eye of the Typhoon" as the cover card for a supposedly Jaden-based Deck).
- Presconstructed Decks in tins (authentic Yu-Gi-Oh! tins are much larger than the fake "deck tins", and always feature a cover card. Athentic tins usually contain booster packs and promo cards, but not presconstructed Decks).
- Some Starter Decks have a Yu-Gi-Oh! logo that says Shonen Nump.
- Some counterfeit cards have a thin layer of plastic covering the card's surface.
- Lack of the "Yu-Gi-Oh! Trading Card Game" logo on the card backing.
- The illegal prints of the Egyptian God Cards are the only exception; there are no logos on the card backing and have red, yellow, or blue-tinted card backing designs. On that note, counterfeit Egyptian God Cards often have the regular coloring and logos on the card backing.
- Cards that are supposedly Exodia in a single card (exceptions being "Exodia Necross", "Exodius the Ultimate Forbidden Lord", and "The Legendary Exodia Incarnate").
As the first set in the TCG, Legend of Blue Eyes White Dragon is a very popular booster pack set. As such, counterfeits have appeared throughout the years. An infamous counterfeit print of 1st Edition booster boxes are well known for the quality of their mimicry. Notable flaws specific to this print include:
- Off-center prints on the booster packs.
- Darker ink.
- The Rare card is placed in the front of the pack (usually located in the middle of the pack).
- Gritty card stock.
- Super Rare holofoil on a supposedly Secret Rare card.
In 2008, Konami sued Upper Deck Company, the worldwide manufacturer of the TCG, who were producing counterfeit cards for a company named Vintage Sports Cards, who had been repackaging these cards with genuine products.