Which Pokémon game introduced Pikachu as the player’s constant companion?

Pokémon Yellow introduced Pikachu as the player’s constant companion.

Released in Japan in 1998, Pokémon Yellow is an enhanced version of the first-generation games. It was designed with the Pokémon anime in mind, so the player begins with Pikachu rather than choosing Bulbasaur, Charmander, or Squirtle as in Red, Green, and Blue.

Pikachu follows the player on screen and refuses to evolve with a Thunder Stone. The game also gives the player opportunities to obtain the three original starter Pokémon, echoing Ash’s early anime journey while still using the basic Kanto adventure.

Pokémon Yellow is not the first Pokémon game and does not replace the original Red and Green releases. It is a later enhanced edition built from that generation’s foundation. In international markets it was titled Pokémon Yellow Version: Special Pikachu Edition and appeared after Pokémon Red and Blue.