All God cards (Japanese version) - Enter 735409784657 as a password to get all God cards.
Aqua Chorus card mistake - If you look at the name of the Aqua Chorus card carefully, it reads "Blue-Eyes White Dragon" on the card instead of "Aqua Chorus".
BC Victory pack card list - Note: You will get this pack after winning the Beginner's Cup Tournament; it has three cards.
Blue Medicine card mistake - The description of the Blue Medicine card reads that both you and your opponent gain 400 LP; however after the card is played only you gain 400 LP.
Deck Destruction Virus and Deck Devastation Virus cards - On the card Deck Destruction Virus, it shows the picture and description of Deck Devastation Virus and vice-versa. However, when they are played they use the effect of the card named at the top of the screen.
Easy KC and experience - Duel Tea Gardner as many times as possible until she asks to be your friend. Answer "Yes" and you will be able to duel her non stop until evening. To get more KC and experience, try this with other feeble or weak characters, such as Serenity and Mokuba.
Getting desired cards - While you are in the house, save the game. Go to the store and make sure you have enough money to buy a pack of cards. If the card you want is not in the pack, turn of the DS. Turn the game back on and you will be back at the house. Go back to the store and you will still have all your money. Repeat this until getting the desired card.
Misspelling - At the Duel Base, Roland says "Duerist" instead of "Duelist".
Never duel difficult duelists - All the easy duelists are out in the daytime. When it turns to evening, walk to your house and go to the shop. Do this until it turns to night. Go to your house and sleep. It will be morning again and you can duel easier duelists once again.
Password Machine - Win the Expert Cup. The Password Machine can now be accessed in the Duel Shop by tapping the slot machine on the left. The Password Machine allows you to type in the ID number of a card you have and insert it into the game (for 1000 KC). Passwords will only work if you have obtained at least 80% of the pack it comes in (you have the card list) or the card is on your card list (total). You can only get one copy of a card, and no God cards.
Passwords - Enter one of the following passwords at the Password Machine to active the corresponding fuction:
Registering as a duelist - After defeating a Duelist eight times, he or she will ask you if they can register you as a Duelist. If you say "Yes", you can choose whether or not you want to play them the next time you encounter them.
Sage's Stone card mistake - The description of the Sage's Stone card reads "Sage's Jewel", but on the actual card itself it has the correct name.
Slifer the Sky Dragon (Japanese version) - Enter 769696675464 as a password to get Slifer the Sky Dragon.
Wing Koriboh cards - Have the Game Boy Advance game Yu-Gi-Oh! GX: Duel Academy in the cartridge slot to start with three Wing Koriboh cards.
Winning at Rock, Paper, Scissors - When dueling against an opponent and you do Rock, Paper, Scissors, remember what you did in a previous duel and use the one that can defeat what you used last time.