From my never completed PC Engine Mahjong site. Here's some basic info on the game I've cut and pasted -
Button I: Action button.
Button II: Backs up from menu screens.
Run Button: Not used.
Select Button: Not used.
D Pad Up: Gameplay menu button. Brings up Kan, Reach, Chi, Pon, Kan, Ron, Tsumo depending on the situation. The far right selection will bring up the cheat item menu.
D Pad Left/Right: Select tile
To completely win the game, beat Haruna and Natsumi four times each, and Chiaki five times.
If you lose a round, it's game over.
More item hearts will be given to you between rounds.
After beating the game, you will be given a cheat code to unlock the animated sequences.
Difficulty: Easy