Starter Decks (スターターデッキ Sutātā Dekki) are the first three pairs of pre-constructed decks released, usually styled after a specific character's Deck, though this does not always ring true. As opposed to Structure Decks, they are made for for beginner players to learn how to play the game. As a result, the guides they give are more generally aimed (unlike Structure Decks, which are much more specific). The mat also does not feature the cover monster, but has a general background design. The original Starter decks (before Starter Deck 2006) had 50 cards, but the newest usually have 40-45 cards each.
The first two, the Yugi and Kaiba Starter Decks, are each half of the first Yu-Gi-Oh card game product released in Japan, set EX.