Things You'll Need
Instructions
Load a "Pokemon Red" or "Pokemon Blue" cartridge into your Game Boy. Travel to Viridian Forest or the Power Plant, both of which are marked on your in-game map. If you have not previously been there before, continue the story as it naturally takes you there.
Walk around tall grass in Viridian Forest or anywhere in the Power Plant until a Pikachu attacks you.
Fight the battle as normal, avoiding water- and flying-types due to their weaknesses. Throw a Poke Ball at Pikachu when its health is nearly empty.
Connect your Game Boy to a second Game Boy containing "Pokemon Yellow." Attach the two devices using either the GBA or multi-link cable. In both games, travel to a PokeCenter and speak with the woman on the second floor to initiate trade.
Select the Pikachu on your copy of "Pokemon Red" or "Pokemon Blue," and select any other Pokemon on "Yellow." This initiates a transfer, and you have another Pikachu on "Pokemon Yellow."