Which battle format debuted in Pokémon Ruby and Sapphire?

The Double Battle format debuted in Pokémon Ruby and Sapphire.

In a Double Battle, each side uses two Pokémon at the same time, creating a four-Pokémon battle instead of the traditional one-on-one format. Moves can target one opponent, an ally, or multiple Pokémon, so positioning and team support become important parts of the strategy.

Pokémon Ruby and Sapphire introduced the format as part of the series' third generation. The games were released in Japan in 2002 for the Game Boy Advance and added several other major mechanics, including Pokémon Abilities, Natures, and Pokémon Contests. Double Battles became a recurring feature in later games and competitive play.

Players sometimes confuse Double Battles with Multi Battles. In a Multi Battle, two trainers are involved on each side, with each trainer controlling one Pokémon; the two formats can overlap but are not identical. Triple Battles and Rotation Battles arrived much later in Pokémon Black and White, while Max Raid Battles belong to the Nintendo Switch era.