At the title screen, enter the 2nd option for the password screen. Now, modify the mahjong pieces to the following numbers: 6, 4, 1, 9, 4, 7, 2. For the final piece, select the 3rd Chinese character. Then, press I and the words "Enter Password" will turn orange. Press II to go back to the title screen and choose the 1st option. Press I three times and you'll be right back at the title screen again. Now, depending on what buttons you press, you can enable several cheats.
During a match, hold Up and press Select, then Up or Down to be able to modify the titles to any number.
Modify Mahjong Titles
While playing, hold Up and press Run.
Restart A Match
During a story intermission, press II to skip forward.
Skip The Story
At the title screen, press II to enable the sound test and use Up or Down to cycle through the songs.
Sound Test
At the conditions screen right before a match starts, press II and you'll automatically win the match.
Win Automatically