The first adaption of the Yu-Gi-Oh! Card Game (known as the Carddas version) was first released by Bandai in September 1998. Albeit popular, only three boosters packs of this version were released before the license of the card game was sold to Konami. The gameplay system used in this version was far more simple and was also less faithful to the anime and manga compared with Konami's OCG/TCG
There are only 13 official rules in this game:
Both players must use the same number of cards as their Decks.
Draw 5 cards from your Deck to form your hand.
Select 1 Monster Card from your hand and play it to start a Battle.
To determine the result of the battle, compare the ATK of your attacking monster with the DEF of the attacked monster.
If your monster's ATK is higher, your opponent's monster is destroyed.
Even if you destroy the opponent's monster, if the DEF of your monster is lower than the ATK of your opponent's monster, your monster is also destroyed.
When the battle ends, draw 1 card from your Deck and you can end your turn.
Each turn will continue like this, until both players' Decks are empty.
Finally, each player counts the total Level Stars of all monsters that he/she destroyed. The player with the highest amount is declared the WINNER.
If you have Spell, Trap or Equip Cards in your hand, you can put them in play face-down.
You can activate your face-down Spell, Trap or Equip Cards at any time during a Battle.
When the effect of a Spell, Trap or Equip Card is used, it is discarded.
When a player's Deck is empty, the Duel will continue until the other player's Deck is empty as well.
Each Monster Card had 1 of these rules printed on its card text. It should also be noted that all Bandai OCG cards had a Yellow Background, regardless if they where Monster, Spell, Trap or Equip Cards (Equip Cards were treated as a distinct class of card, not as Spell Cards).