Which game inspired Satoshi Tajiri to imagine trading items between players for Pokémon?

Dragon Quest II inspired Satoshi Tajiri to imagine trading items between players for Pokémon.

While playing Dragon Quest II, Tajiri tried to obtain a rare item dropped by an enemy but could not get it. Ken Sugimori, who was also playing the game, had obtained two copies. Tajiri wished the extra item could be transferred between players.

The Famicom did not provide a way to trade items between separate games, but the later Game Boy included a communication cable. Tajiri realized that the cable could support exchanging creatures, turning a hardware feature into the foundation for Pokémon’s social play.

Final Fantasy Legend also influenced Tajiri because it showed him that a Game Boy could support more than action-oriented games. However, Dragon Quest II is the specific inspiration associated with the trading idea that became central to Pokémon.