Yami Yugi and Mokuba Kaiba ' s Duel Yami Yugi and Mokuba Kaiba Dueled during the Duelist Kingdom tournament , in the " Yu - Gi - Oh ! " anime . It is based on a similar Duel from the " Yu - Gi - Oh ! " manga . Events . Prior . While Maximillion Pegasus tried taking over KaibaCorp , Mokuba swallowed an important key , so Pegasus had him kidnapped until the key could be retrieved . Mokuba was brought to Pegasus Castle on the Duelist Kingdom island . However Mokuba escaped the castle . Mokuba knew that Pegasus ' plan involved defeating Yugi Muto in the finals of the Duelist Kingdom tournament , so Mokuba tried to eliminate Yugi from the tournament before that could happen . He stole a Deck and five Star Chip s form one of the participants and planned to use them to defeat Yugi . Yami Yugi , Joey Wheeler and their friends saw the boy , whom Mokuba had stolen from , being restrained by Kemo and told he was to be sent off the island for losing all his Star Chips . The boy explained that the Star Chips had been stolen , but Kemo was unsympathetic . Joey offered to catch the thief and asked that Kemo not remove the boy from the island until then . Joey then added that he would keep half the Star Chips as a reward . While searching for the thief , Yami and Joey saw the boat eliminated participants leaving the island and among them was the boy whose Star Chips had been stolen , meaning they would not be able to return the Star Chips to him . Mokuba masked with a bandanna appeared before Yami Yugi and his friends . They recognized the person before them as the thief , but did not immediately recognize that he was Mokuba . Yami accepted Mokuba ' s Duel request , despite knowing he was the thief . The two of them wagered their five Star Chips . As they lay down their Star Chips , Yami noticed that Mokuba did not have a Duel Glove , meaning he was not invited to the tournament . He wondered if the thief stole the Star Chips just to challenge him and started to become suspicious of something . Meanwhile , Yami ' s friends wondered why he accepted the Duel , when his opponent was clearly the thief . The Duel . 1st turn : Mokuba Mokuba Summoned " Man - Eating Plant " . 2nd turn : Yami Yami Summoned " Winged Dragon , Guardian of the Fortress " . " Winged Dragon , Guardian of the Fortress " attack ed and destroy ed " Man - Eating Plant " ( Mokuba : 2000 → 1400 Life Points ) . Mokuba Summoned " Krokodilus " . Yami attacked " Krokodilus " with " Winged Dragon , Guradian of the Fortress " . Joey thought that the thief was not very good and Téa agreed that he was no match for Yami Yugi . Yami advised Mokuba to give up , as the game is not so simple that it can be won with stolen cards . Mokuba knew he did not have a chance of winning , so tried to take Yugi ' s Star Chips instead . The Duel was not finished . Aftermath . Mokuba made a grab for the Star Chips , only managing to grab seven of the ten , but Yami caught him by the wrist , before he could escape . Yami then removed Mokuba ' s cap and bandanna , revealing his identity . When questioned about why he tried to steal Yugi ' s Star Chips , Mokuba told them that it was not for revenge . He told them about Pegasus ' plan to take over KaibaCorp , which required Pegasus to defeat Yugi in an official Duel . Mokuba had thought if he could make Yugi lose all his Star Chips , he would be disqualified before Pegasus could Duel him . Yami and his friends managed to convince Mokuba that they would help him and somehow find a way to beat Pegasus , whom Mokuba had heard was unbeatable . However when Mokuba tried returning the Star Chips , Kemo appeared and warned them exchanging Star Chips outside of a Duel was against the rules and could be punished with disqualification . So , Yami challenged Kemo to a Duel for the Star Chips , however Kemo himself did not play games , so he arranged Ghost Kaiba , as an opponent for Yami .