Pokémon Blue Version, along with its sister game, Pokémon Red Version, were the first Pokémon games released in North America. In Japan, Pokémon Green was released with Red, and Blue was released later as a minor upgrade to Green. North America took the Blue version's graphics & engine, and from it, made Pokémon Red and Blue, but maintained their exclusive Pokémon. The original Japanese Green & Red were basically the same, except for slightly different (perhaps worse) graphics.
Both games are exactly alike except that a handful of Pokémon (Pocket Monsters) are exclusive to each version. The two versions were designed to be bought by different people, who would then use Game Boy link cables to trade and battle their collected Pokémon.
The massive success of the game revitalized the Game Boy, and revived many returning franchises such as Monster Rancher and prompted Japan to port over new ones like Digimon. Many other games such as DemiKids and Mega Man Battle Network borrowed the "Two Version" format for their games as well.
When the series made its way to the Game Boy Advance, remakes of Red & Blue were published with better graphics, some new locations and updated features, and a few of the new Pokémon. These were Pokémon FireRed Version and LeafGreen Version. The purpose of these remakes was to allow players to catch and trade the original 150 Pokémon and bring them into their new Game Boy Advance games, since the original Game Boy and Game Boy Color games were not compatible with the new link cable.
Japanese and English Versions
Pokémon Red and Pokémon Blue were the first Pokémon games to be released in the US, on September 30, 1998. The Japanese equivalents were Pokémon Red and Green, released on February 27, 1996. However, the sprites for Pokémon Red and Green was not used for the Blue version in the US. The Japanese version of Pokémon Blue was the third Pokémon game released in Japan on October 10, 1996. It was released as a graphical upgrade from the original games, Pokémon Red and Green, and was used as the engine for the American Pokémon Red and Blue. In the Japanese Blue version the Mew Glitch was removed, the catch rate was adjusted, and the Cerulean Cave is different from the Japanese Pokémon Red and Green and was used for the US version of Red and Blue.
You are a young boy in a world where creatures called Pokémon exist in the wild. Their purpose is to be pets, or caught and trained for competitive battle. One day, your neighbour Professor Oak offers you one of three Pokémon: Charmander, Bulbasaur or Squirtle. Once you choose, Oak asks you to fill up his Pokédex by seeing and catching as many Pokémon as possible.
Oak's nephew Gary (Shigeru in Japan) is on the same mission. While you're filling up your Pokédex, you are also looking to become the Pokémon Champion by defeating every Gym Leader in your country of Kanto, then defeating the Elite Four in the Pokémon League.
There are 11 Pokémon which are only found in this version.