Counterfeit

Counterfeit cards are fake trading cards. These can be easily recognized as most fake cards will have oddly colored backs or images or, in a holographic counterfeit the card will not shine when held up to light. They may also have inaccurate ATK and DEF values. Some cards may have a slightly faded look. 1st edition fakes can be identified through the lack of a gold sticker at the bottom of the card (sometimes it is there, but it is silver). However, some legitimate cards are misprinted to have the wrong color sticker. There have also been cards that claim to be Exodia in one card--unless it is the Shonen Jump promo 'Exodius the Ultimate Forbidden Lord' or 'Exodia Necross, it is fake. Some cards are easily identified as counterfeit because they are Spell, or Trap cards that have ATK and DEF values as illustrated below. In addition, some may have their rarity written at the end of the card's description or effect, they may be very poorly written, have the wrong font or logo or the image may not be central. But the most common way of identifying a fake is by looking at the stars in the image. If they are irregular and large in comparison to others, it is a fake card.

Fake booster packs/boxes
Fake boosters invariably contain fake cards. Most fake boosters and booster boxes have the following tell-tale signs:
 * Bad picture quality (except for Duel Terminal cards,Duel Terminal cards are quite blurr.)
 * Reversed Konami logo
 * Misspellings
 * White bordered text
 * On boosters, the seals at the top and bottom should be vertical not horizontal.
 * No "English Edition" sign on top of the booster.
 * No gold/silver sticker
 * Strange logo, as in "New yu-gi-oh!" or a "Yu-Gi-Oh GX"
 * Numerical code missing in the lower left corner.
 * Copyright 1996 Kazuki Takahashi missing from lower right corner next to the sticker.
 * On boxes, there is a completely unrelated cover card to match the set name, or that the set name does not exist at all
 * On decks, cover card sometimes does not even relate to the character featured on the box (e.g. Eye of the Typhoon as cover card for a supposedly Jaden-based Deck)
 * Decks in tins(note that there ARE real yugioh tins,but they are much bigger then this fake "deck tins".