List of cross-generational references

The four generations of Pokémon games, taking place in the same universe, have had multiple references to each other. Not only do the games reference their same-generation counterparts (with the player's default name being the version played and the rival's being the counterpart version in the first two generations), but games released later in the series typically will feature references to events of past generations.

Please note, of course, that this does not include Pokémon. While Pokémon released in previous generations will always appear, they are not a reference to the generation itself.

Generation II

To Generation I

• Not only is the Kanto region a playable area during the games, but several of the events of Generation I are spoken of as having happened three years previous.
• Red, the player character of the first games, is found training in Mt. Silver and can be battled.
• Blue, the rival character of the first games, has become the Gym Leader of Viridian City.
• The Berserk Gene, a held item, is found near the former entrance of the now-collapsed Cerulean Cave, where Mewtwo once hid.

Generation III

To Generation I

• Brawly is said to have once trained alongside Bruno, who is a member of Kanto's Elite Four.
• The Oceanic Museum in Slateport City has two water samples, one of which is from Kanto.
• Pokémon FireRed and LeafGreen in their entirety are a reference to Generation I's events, while the credit sequence references the version mascots of Red, Green, Blue, and Yellow.

To Generation II

• The player-controlled character of Ruby, Sapphire, and Emerald is said to have moved at the beginning of the game with his/her family from the Johto region, the main setting of the Generation II games.
• The Oceanic Museum in Slateport City has two water samples, one of which is from Johto.
• The branch of Team Rocket in the Sevii Islands seems to be the same branch which attempted to revive Team Rocket during Generation II, with plans to use magnetic waves to evolve Pokémon. Their lead scientist also tells that Giovanni's son has red hair, a possible reference to Silver.
• Janine, Koga's daughter and future Leader of Fuchsia Gym, appears in Fuchsia City, and tells the player that she is training to use Poison Pokémon as well as her father. She is unfortunately misnamed as Charine in the English translation of FireRed and LeafGreen, however.
• One of Professor Oak's assistants will state that he is to get a radio show sometime in the near future.

Generation IV

To Generation I

• Professor Rowan is said to have developed the Sinnoh Dex with help from a Pokémon professor from Kanto.
• Professor Oak himself comes to Sinnoh to give the player the National Dex, and can always be found in a house in Eterna City thereafter.
• A Ninja Boy near Celestic Town says he wants to train with a ninja Gym Leader in a faraway land.

To Generation II

• A news report of a red Gyarados begins the game.
• A man, who gives the player a Happiny egg, says that Professor Elm recently announced that eggs kept with a trainer will eventually hatch.
• Jasmine, one of Johto's Gym Leaders, appears to give the player HM07: Waterfall.
• A man in Valor Lakefront states that he would like to see a silver-colored Pokémon that resides in the Whirl Islands, a rainbow-colored Pokémon that resides in the Tin Tower, and Clefairy dancing in Mt. Moon sometime during his life.

To Generation III

• A man in Hearthome City, who says he is from the Hoenn region, will show the player to the Contest Hall, a feature originally introduced in Hoenn.
• A man in Valor Lakefront states that he would like to see a rocket launch from the Space Center in Mossdeep City sometime during his life.
• A woman west of Pastoria City used to work at the Weather Institute of Hoenn and will give out weather-changing TMs for Shards.