At girl select screen, press A, A, B, Right, A, Left, B, Down, A, Up, then select any girl and start the game. From now on, by pressing the A Button you will be able to select any mahjong tile to add to your pool.
In-game during the player's move on the second controller, press the sequence A, A, B, Right, A, Left, B, Down, A, and Up.
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