The first Pokémon games, Pokémon Red and Green, were released in Japan featuring Pikachu as one of the original Pokémon species.
Pikachu was chosen as the official mascot of the Pokémon franchise, becoming the most recognizable and iconic character representing Pokémon worldwide.
Pokémon Yellow, inspired by the Pokémon anime featuring Pikachu as the player's starter Pokémon, was released allowing players to have Pikachu follow them in-game.
The Pokémon anime debuted in Japan with Pikachu as the main companion of Ash Ketchum, greatly increasing Pikachu's popularity.