Which Game Boy feature enabled players to trade Pokémon between two original game systems?

The Game Boy Link Cable enabled players to trade Pokémon between two original game systems.

Pokémon Red and Green were designed around the idea that players would connect separate Game Boy consoles. Each version contained Pokémon that could not be obtained in the other, so trading was necessary for players who wanted to complete the Pokédex.

The cable also supported battles between players. This turned Pokémon into a social experience rather than a purely single-player role-playing game. Satoshi Tajiri’s concept drew directly on the possibility of creatures traveling through the Game Boy’s link connection.

The feature is sometimes confused with later wireless trading systems. Subsequent Pokémon games used infrared communication, wireless adapters, local wireless functions, and internet services. The original releases depended on a physical cable and two compatible Game Boy systems.