This trick requires two memory cards and controllers. Save a file (the one you want to keep) on a memory card. Next, on a second memory card, create a file that is temporary. Get considerably far or as far as you would like. When you get a card you really like and you cannot get more of them because of lack of experience, copy your file that you want to keep on the first memory card as many times as desired. Then, go to two player mode. Place your first copied file as player one and the temporary file (on the second memory card) as player two. Bet the cards you want to copy from player one, then lose the match. Switch to the file that is (non-copied on the first memory card) and have player two bet the cards that they just won. Win the match for player one. Repeat this as many times as desired. To copy a file, go to single player and save under open slots.

Assume you have a Red Dragon card that is to be duplicated. First, in your main game (with the Red Dragon), save it in two separate files (hereafter know as 1A and 1B). Then, start a new game, and name the character with a different name than in 1A and 1B. Save it in a separate file (known as 2). Start a multi-player game. For player one, load save 1B. For player two, load save 2. Bet the Red Dragon in player 1B's possession. Then, have player 1B intentionally lose to player two, so that player two gets the Red Dragon Card. Then, start a new multi-player game and have player one load save 1A and player two load save 2. Then, have player two bet the Red Dragon card. Have player two intentionally lose to player 1A, so that player 1A wins the Red Dragon. Now, go to one player mode and load save 1A. Player 1A now has the Red Dragon card. To do this trick multiple times, while in one player mode have player 1A save the game in save slots 1A and 1B. Now, player 1B has the card as well. You can repeat this as many times as needed. Note: The Red Dragon is transformed from a Lizardman or a Red Lizard after getting 6000 experience points.