How to Duplicate a Master Ball in "Pokemon Crystal"

The Master Ball is one of the most powerful items in "Pokemon Crystal," letting you capture any Pokemon in the game instantly. There is only one catch: Only one Master Ball is available in the game through normal means. However, there is a method to duplicate your Master Ball using your Pokemon and the PC available at any Pokemon Center, letting you get as many as you may need. Save your game before attempting the duplication glitch.

Get the Master Ball from Professor Elm after collecting all eight gym badges in Johto. Attach the Master Ball to any Pokémon in your party.

Head to any Pokémon Center and approach the PC in the upper right corner of the room.

Press “A” to access the PC, and then select “Bill’s PC.” Select an empty box and deposit the Pokémon holding the Master Ball into the empty box.

Select “Change Boxes” and the game will automatically start to save. Immediately after the words “Saving the game…” appear on screen, turn off your Game Boy Color.

Turn your Game Boy Color back on and load your save file. You will find two copies of the Pokémon: one in the box, and one in your party. Each will have a copy of the Master Ball.