→In the games
In the core series games, except [[Pokémon: Let's Go, Pikachu! and Let's Go, Eevee!]], normally when the player encounters a [[wild Pokémon]] they battle that Pokémon. (In Let's Go, Pikachu! and Let's Go, Eevee!, as well as in the [[Safari Zone]] and [[Pal Park]] in other core series games, the player has the opportunity to catch the wild Pokémon but cannot battle it.) A battle between two Trainers starts when they make eye contact, which players can do by interacting with the other Trainer.
When a Pokémon [[Fainting|faints]] in battle, it may cause its opponent to gain [[experience]] or [[effort values]]. After all of either side's Pokémon have been defeated, the battle has been won, and the loser must pay out some amount of money to the winner, determined based on the level of the Pokémon and
[[Trainer class|type of Trainer ]] defeated. In the core series games, if the player's Pokémon have all been defeated, he or she will [[black out]] (in [[Generation I]] and since [[Generation IV]]) or white out (in [[Generation II]] and [[Generation III]]), and be teleported back to the most recent [[Pokémon Center]] that was visited, or to his or her home, if a Pokémon Center has not yet been visited.
Some battles, most notably battles fought between two players or in certain [[Battle facility|battle facilities]], will not affect the participating Pokémon's experience, EVs, or [[friendship]]. The battle's outcome will not cause money to be awarded to or deducted from participating trainers. Pokémon seen during these battles will not be registered in the [[Pokédex]]. Usually, [[bag]] [[item]]s are not allowed in these battles, and all Pokémon and [[held item]]s are restored after each battle.