Cheating is the term referring to not following game rules during a Duel Masters game.
Doing so results in disqualifications of the player in the match (Also known as a Judge-kill), and banning from entering further tournaments.
Examples of cheating
- Bringing Premium Hall of Fame cards in a deck or more than 1 copy of a Hall of Fame card ( outside of Hall of Fame Zero Duel).
- Having more than 40 cards in a deck in the Japanese format.
- Shuffling the first hand back into the deck and drawing 5 cards again in order to get good draws. 
- Using a way of shuffling that will guarantee a massive amount of shield triggers in his shields.
- Looking at shields when returning a shield to hand via effects like Aqua Super Emeral.
- When failing a creature Revolution 0 Trigger such as Bolshack Dogiragon, the player uses swift moves to evolve the creature from a creature in hand.
- Using cards without fulfilling civilization requirements.
- Using Proxy Cards in a duel.
- Drawing more than 1 card at the start of the turn without another effect that allows so.
- When returning shields to hand, the player quickly swaps the shield in his hand with a Shield Trigger in his hand not originally in the shields.
- Removing the seals of FORBIDDEN STAR ~World's Last Day~ multiple times in a turn.
- Using electronic devices to disrupt the match in official tournaments.
- Stalling the game by playing slowly.
Punishments of Cheating
There are no examples of sanctions against cheating in the official Duel Masters guidebook. However, it is listed that if proof of cheating exists, game judges related to Takara Tomy and Wizards of the Coast can instantly end the game by giving the other side a win. If further implications are present, the judges can ban the player from entering all official and officially sponsored tournaments and events.
In online duels, cheating can be sanctioned by surrendering or aborting the duel and giving the case to the admins, or allowing other users to dispute the game depending on the website.
In the Anime
Benny Haha is often known for cheating in the anime, such as swapping shield triggers, slipping cards into his hand, And peeking at other's hands using machines stalled in the dueling room. This continued for all of his history, even in Versus Revolution.
Many of the early enemies in the Duel Masters series such as Vivian Widow's cast and the Black Soldiers are involved in cheating in some way. This continued in enemies in later episodes such as victory where Rikishi and Shachihoko were known for cheating in duels. Benny Haha also cheated in Versus Revolution in his duel against Basara.
Ironically, the more dangerous antagonistic organizations such as Fua Duelists and Adam's guards never seem to cheat, bur instead rely on their sheer brutality and power to antagonize the protagonists.
In a gag episode, Grandpa Danger cheated for the entire duel against Katta. For example, he placed his starting hand into his mana zone right at the start, blocked an attack by inflating his head, used multiple proxy cards in his deck and attempted to summon Bolshack Dogiragon without paying the correct amount of mana. However, it was for joke purposes.
The other corocoro collaboration in Joe Kirifuda's saga, Keshikasu-Kun also cheated in his duel against Joe, in which he mended the shields using plasters and used proxy cards that costed 1 mana. Again, it was for Joke purposes instead of out of malicious intent.
In the end of Versus Revolution Final, Joe Kirifuda created several proxy cards such as Jolly the Johnny Joe and an overpowered version of Yattareman and used them in his deck. However, since he is a kid and that he was learning the important concepts of dueling, he is allowed to do so for all 7 episodes of his appearance in Versus Revolution Final.
- ↑ There are no Mulligans in official Duel Masters tournaments. Therefore, any attempt to mulligan without a judges permission is cheating.