Counterfeit

A counterfeit card is a fake trading card. Most counterfeit cards in the context of Yu-Gi-Oh! are of OCG or TCG cards, or are made to mimic them. Counterfeit cards are usually made with the express purpose of selling them as real cards to make a profit, which distinguishes them from fan-created cards, which may be sold as art but not as real cards.

Many counterfeit cards can be easily recognized by such things as oddly colored or low-quality card backings or images,or very poor grammar in card names, effects, and other card text, which may use the wrong font or be incorrectly sized. Counterfeit Spell and Trap Cards may have ATK and DEF values and maybe even level stars printed on them, and some cards may have their rarity printed following their effect or description.

Fake trading cards are often sold in markets, non-legit stores, and online.

Fake booster packs/boxes
Most fake boosters and booster boxes have the following tell-tale signs:
 * Bad picture quality (Duel Terminal cards are often blurred because of their parallel coating and are much darker than other cards; as such, their artworks should not be confused with this)
 * Reversed Konami logo or incorrect spelling of "Konami" (e.g., Konaini)
 * Incorrect Format
 * the use of profanity or wrong grammar
 * Wrong card name, effect, Level, artwork, or stats (the name is often the translated Japanese name)
 * Incorrect English grammar
 * Bright Colored pictures
 * White bordered text
 * Incorrect terminology in card descriptions (e.g. one of the cards in the example pictures below uses "Adversary"/"Rival" instead of "Opponent", "Life score" instead of "Life Points", and "bout" instead of "Phase")
 * On boosters, the seals at the top and bottom should be vertical, not horizontal.
 * No "English Edition" sign on top of the booster.
 * No Eye of Anubis, or the Eye of Anubis is not reflective (though OCG cards with the original layout all lacked the Eye of Anubis).
 * Incorrect Type or Attribute
 * Incorrect ordering of card type. Normally, the Monster's Type is listed first, followed by any subtypes, e.g. "Machine/Effect", "Warrior/Synchro/Effect", or "Dragon/Spirit".
 * Rarity that is not holographic (e.g. a card has gold letters that are not reflective).
 * Strange logo, as in "New Yu-Gi-Oh!" or both "Yu-Gi-Oh! GX" AND "Yu-Gi-Oh! 5D's" logo in one pack/box/tin.
 * Card Number/Limitation Text missing from the lower left corner. There are some real cards, such as "Labyrinth Wall", which do not have a Card Number.
 * Sound, God or Land as an attribute.
 * Copyright text (&copy;1996 KAZUKI TAKAHASHI) missing from the lower right corner next to the Eye of Anubis.
 * On 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 cover card for a supposedly Jaden-based Deck)
 * Decks in tins (note that there ARE real Yu-Gi-Oh! tins, but they are much bigger than the fake "deck tins", and always shows the cover card that match the tin).
 * Counterfeit cards sometimes feel waxy or have a thin layer of plastic over the card's surface.
 * Lack of the "Yu-Gi-Oh! Trading Card Game" logo on the card's backing (the Egyptian God Cards are the only exception; they have no logos on the back and have red, yellow, or blue-tinted backing designs. On that note, fake God Cards may have the normal coloring and logos on the back that all the normal cards have).
 * "Machine" almost always written as "Maching", "Warrior" almost always written as "Fighter" and "Fiend" almost always written as "Insect".
 * Incorrect writing of Type as well as Attribute (Attributes not written in capitals such as "fire" instead of "FIRE", or a type written with no capital such as "beast-type" instead of "Beast-type").
 * Monster Cards which read "Family" or "Race" after their Type (for example, "Dragon Family", "Fighter Race".
 * Spell Cards or Trap Cards have ATK/DEF.
 * Cards that claim Exodia as a single card (except "Exodia Necross" or "Exodius the Ultimate Forbidden Lord").
 * Incorrect fonts.
 * Cards with phrases such as "Warrior-Junta" in the type.
 * Card types which feature the type and sub-type being seperated by a period rather than a slash.
 * Fusion Monsters which list "Melting", "Mix" or "Combination" rather than "Fusion" in the type. Likewise, Ritual Monsters which list "Ceremony" instead of "Ritual".
 * Attribute symbols which do not feature the kanji symbol for the appropriate attribute, instead just having the word, such as "Light" or "Fire".
 * Most counterfeit cards have strange reflective star designs on them, somewhat similar to Duel Terminal cards.