Viridian City/Places of interest/Trainer House

In Generations and, the Trainer House replaces the Pokémon academy in the center of Viridian. The first floor is occupied by a handful of people, while the basement is primarily dedicated to a battlefield. In the basement, the undefined may battle other Trainers once a day.

In Generation II, the opposing in the basement will be the last person the player has used Mystery Gift with, with whatever party they had when Mystery Gift was used. If the player has never used Mystery Gift with anyone, the opposing Trainer will be.

In Generation IV, the player will initially only find  in the basement. When the player meets another Trainer via the Pokéwalker and re-syncs the Pokéwalker back to their game, the other Trainer will also appear in the basement with their party. Up to 10 additional Trainers may be encountered in this way. Any Pokémon in a Trainer's party above level 50 will have their level reduced to 50. Battles here give no experience or money, but the player will receive 1 BP for each victory.