I remember when Pokémon Black and White Versions were released in 2011, many fans wondered why Game Freak had decided to develop the fifth generation of Pokémon games for Nintendo DS, as opposed to the brand new, and significantly more powerful, Nintendo 3DS. When Black and White Versions 2 were announced a year later, even more criticized the decision to release the games on what was by then an obsolete console.
As it turns out, Game Freak had very good reason for developing these games on the lesser of the two beasts: the next generation of Pokémon had already begun development. In the latest issue of Game Informer, Junichi Masuda reveals that the first ideas for Pokémon X and Y were coming in as early as June 2010—three months before the release of Pokémon Black and White in Japan.
“…the conceptual planning for Pokémon X and Pokémon Y began before Pokémon Black Version and Pokémon White Version were released. The idea for the game first rose around June of 2010. Then we spent three years developing the game, and, when you include the localization work, it ended up being a big project on which around 500 people were involved.” — Junichi Masuda
For games so rich in content as X and Y, it’s no surprise that it took three years to develop the game, even with over 500 collaborators. It just goes to show how much effort went into creating the world of Kalos and the hundreds of character models for in-game Pokémon battles.
Source: Game Informer