Level Select
Note that this cheat is only available in AVE releases of this game. At the stage number screen, press Select, A, A, B, B, B, A, A, B, B, B, A, B, A, B. Some different music will start playing. Press A or B to select the stage number up to 7-1, and press Start play it.
Level Select
Note that this is only available in Asian releases of this game, "Idol Shisen Mahjong", released by Hacker International. At the stage number screen, press Select, A, B. The music will start playing. Press A or B to select the stage number from 1 to 21, then press Start to view the stage's final image. Press Start to return back to the stage number screen, where you can now play selected level or enter the cheat one more time and select another stage.