Pocket Monsters Aka [Model DMG-APAJ-JPN]

Released on February 27, 1996 in Japan. They sold rapidly, due in part to Nintendo's idea of producing the two versions of the game instead of a single title, prompting consumers to buy both.

Originally called Capsule Monsters, the game's title went through several transitions due to trademark difficulties, becoming CapuMon and KapuMon before eventually settling upon Pocket Monsters.

Tajiri pitched the concept of Pocket Monsters (known as Pokémon outside Japan) to Nintendo's staff in 1990 and was met with skepticism. They believed his ideas were too ambitious and found it difficult to see the appeal. However, Shigeru Miyamoto saw great potential in the idea and convinced the company to go ahead with the project.

The initial concept for Pokémon stemmed from the hobby of insect collecting, a popular pastime which game designer Satoshi Tajiri enjoyed as a child. While growing up, however, he observed more urbanization taking place in the town where he lived and as a result, the insect population declined. Tajiri noticed that kids now played in their homes instead of outside and he came up with the idea of a video game, containing creatures that resembled insects, called Pokémon. He thought kids could relate with the Pokémon by individually naming them, and then controlling them to represent fear or anger as a good way of relieving stress. However, Pokémon never bleed nor die in battle, only faint – this was a very touchy subject to Tajiri, as he did not want to further fill the gaming world with "pointless violence".

When the Game Boy was released, Tajiri thought the system was perfect for his idea, especially because of the link cable, which he envisioned would allow players to trade Pokémon with each other. This concept of trading information was new to the video game industry because previously connection cables were only being used for competition. "I imagined a chunk of information being transferred by connecting two Game Boys with special cables, and I went wow, that's really going to be something!" said Tajiri. Upon hearing of the Pokémon concept, Shigeru Miyamoto suggested creating multiple cartridges with different Pokémon in each, noting it would assist the trading aspect. Tajiri was also influenced by Square's Game Boy game The Final Fantasy Legend, noting in an interview that the game gave him the idea that more than just action games could be developed for the handheld.

The main characters were named after Tajiri himself as Satoshi, who is described as Tajiri in his youth, and his long-time friend, role model, mentor, and fellow Nintendo developer, Shigeru Miyamoto, as Shigeru. Ken Sugimori, an artist and longtime friend of Tajiri, headed the development of drawings and designs of the Pokémon, working with a team of fewer than ten people who conceived the various designs for all 151 Pokémon. Atsuko Nishida created the designs for Pikachu, Bulbasaur, Charmander, Squirtle, and many others. Sugimori, in turn, finalized each design, drawing the Pokémon from various angles in order to assist Game Freak's graphics department in properly rendering the creature. Music for the game was composed by Junichi Masuda at his home on a Commodore Amiga computer. It utilized the four sound channels of the Game Boy to create both the melodies and the sound effects and Pokémon cries heard upon encountering them. He noted the game's opening theme, titled Monster, was produced with the image of battle scenes in mind, using white noise to sound like marching music and imitate a snare drum.

Tajiri always thought that Nintendo would reject his game, as the company did not really understand the concept at first. However, the games turned out to be a success, something Tajiri and Nintendo never expected, especially because of the declining popularity of the Game Boy.

Tajiri said that the Poké Ball concept was inspired by Ultraseven's Capsule Monsters from the tokusatsu superhero television series Ultraseven (1967–1968).