Booster 4 is a Japanese Booster Pack in the Yu-Gi-Oh! Official Card Game that was released on August 26, 1999. This set was sold only in Carddass vending machines.
Like other cards printed early on in the game, the cards have no printed set numbers, and lack the distinctive Eye of Anubis Hologram in the lower right-hand corner of each card.
Of the 40 cards in Booster 4, all but 11—"Barrel Rock", "Big Insect", "Brave Scizzar", "Emperor of the Land and Sea", "Fairy of the Fountain", "Fiend Kraken", "Gorgon Egg", "Mech Bass", "Orion the Battle King", "Spirit of the Mountain", and "Winged Egg of New Life"—have since been printed in the Yu-Gi-Oh! Trading Card Game.
Booster 4 contains 40 cards. Rarities are distributed as follows:
The set also contains six non-playable FAQ Cards.