Generation I

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Generation I
Pokémon Yellow Version
Title screen of Pokémon Yellow Version
Debut EN September 28, 1998
JA February 27, 1996
Pokémon 151
Main games Red, Green, Blue, and Yellow (Japan)
Red, Blue, and Yellow (International)
Region(s) introduced Kanto
Battle arena games Stadium (Japanese), Stadium (International)
Side games Trading Card Game, Pinball, Snap, Puzzle League
End EN October 15, 2000 (748 days)
JA November 21, 1999 (1363 days)

The first generation (Japanese: 第一世代 first generation; ポケットモンスター赤・緑シリーズ Pocket Monsters Red and Green Series) of Pokémon games, commonly referred to by fans as Generation I (Japanese: 世代 Generation I), is the initial set of Pokémon games released.

This generation started with the Japanese games Pokémon Red and Green, later joined by Blue. These three games were combined into the international Pokémon Red and Blue. The special edition Yellow was later released as well. Two side games were also released: the Japan-only Pokémon Stadium and its sequel, released internationally as Pokémon Stadium.


The Japanese name 「ポケットモンスター赤・緑シリーズ」 (Pocket Monsters Red and Green Series) has been used in the website, referring to the games Pokémon Red, Green, Blue, Yellow, Stadium (Japanese), and Stadium (English).[1][2][3]

Although the term "Generation I" is usually considered fan terminology, it was used in the cast commentary for POKÉMON Detective Pikachu, and the subtitles give the Roman-numeral form.


The Generation I games were developed beginning as early as 1990 from an idea that Satoshi Tajiri had thought of and pitched to Nintendo with the help of Shigeru Miyamoto. The inspiration for many of the key mechanics introduced in this generation came from Tajiri's childhood interest in bug collecting, with the trading system between two Game Boys being thought of when he imagined a caterpillar crawling across the Game Link Cable between two systems.

This generation was localized into English, with initial attempts to keep the Pocket Monsters name for international use blocked due to the Monster in My Pocket franchise leading to the release as "Pokémon". Further alterations made in the localization included the combination of Red, Green, and Blue into the English versions of Pokémon Red and Blue, using Red and Green's wild Pokémon encounter lists but Blue's slightly improved graphics. The simultaneous release of the games and anime led to an almost-overnight surge in popularity, cementing the Pokémon franchise firmly as a Nintendo mainstay alongside Super Mario and The Legend of Zelda.

Two battle arena games were released in this generation: the mostly-incomplete Pokémon Stadium (Japanese), which went unreleased outside of Japan and only allowed use of 40 Pokémon, and the improved Pokémon Stadium, which featured several special battle modes and a Gym Leader Castle where players could take their fully-trained teams for matches against the Kanto Gym Leaders, Elite Four, and Champion.

The games proved popular enough that, eight years after their original release, they received remakes in the form of Pokémon FireRed and LeafGreen, as the original versions are incompatible with Generation III and onward. Pokémon Yellow received a remake twenty years after its original release in the form of Pokémon: Let's Go, Pikachu! and Let's Go, Eevee!.

The storyline of the Kanto region is contemporaneous with the Hoenn story of Generation III, as revealed by details in both the Hoenn-based games as well as the later remakes of Generation I. The storylines of the Generation II and Generation IV games occur three years after this generation, with details about this link explicitly noted throughout the Johto-based games.


Generation I introduced the key Pokémon gameplay elements which have remained to this day, as well as a system of game releases now considered by fans to be the "standard formula". While many of the features enjoyed in the more recent generations are later additions to the series, the following have their origins in Generation I:

  • The player has a party of up to six Pokémon with them, which can be used in battle against opponent Pokémon Trainers or wild Pokémon.
  • A PC-based Pokémon Storage System, made up of 12 boxes of 20 Pokémon each and developed by Bill, a Pokémon fanatic, is available to store reserve Pokémon not in the party (up to 240 total).
  • 151 species of Pokémon, with many related to each other by way of evolution.
  • A complex battle system, including:
    • Five stats—HP, Attack, Defense, Speed, and Special—which each Pokémon has. Different Pokémon have different stats, even among the same species.
    • 15 different types, which each Pokémon species has inherent to itself.
    • 165 unique moves, restricted to four per Pokémon, each with its own type, accuracy, and base power.
  • The Pokémon League challenge, consisting of Kanto's eight Pokémon Gyms, scattered across the region with each specializing in a different type, and the Elite Four and Pokémon Champion, awaiting challengers at Indigo Plateau.
  • A linked trade and battle system between two Game Boy systems, allowing players to exchange Pokémon they caught for a Pokémon owned by another person or to battle against each other to test their skills. Some Pokémon have to be traded so that they can evolve.



Main article: Kanto

Generation I introduced the first region to the Pokémon series, which, though unnamed in the original English games, is named in Japanese as Kanto, after the region of Japan it is based on. The name has since passed into English, first being used in Super Smash Bros., and subsequently being noted in all games since.

First partner Pokémon

At the outset of the player's journey, he will have no Pokémon on hand, and venturing outside of Pallet Town is impossible, as Professor Oak will stop him and bring him back to his lab, where three Pokémon await both the player and his rival.

The first partner Pokémon of the Kanto region began the recurring three-type trio of Grass, Fire, and Water, with the player's choice being between Bulbasaur, Charmander, and Squirtle. Much as in later generations as well, the rival will choose whichever of the three has the type that is super effective against that of the player.

The choice of a first partner Pokémon can make the beginning few Gyms change in difficulty, but it does not affect much in the long run aside from the rival's party. Bulbasaur is known by many to be the easiest to start with, as its Grass-type weakens the first two Gyms and resists the attacks of the third. Squirtle is known as the second easiest, as Water types also weaken the first Gym; however, it can prove difficult mid-game if the player has not caught a Pokémon that can resist the later Gyms. Charmander is widely regarded as the hardest of the trio, as Fire-type moves do little damage against the first two Gyms' Pokémon, and there are few opportunities to capture a Pokémon that can counterbalance its weaknesses against the first several Gyms.

001Bulbasaur RB.png
004Charmander RB.png
007Squirtle RB.png
Grass Poison Fire Water
Ivysaur Ivysaur Charmeleon Charmeleon Wartortle Wartortle
Grass Poison Fire Water
Venusaur Venusaur Charizard Charizard Blastoise Blastoise
Grass Poison Fire Flying Water

In Pokémon Yellow, instead of the normal trio found in Red, Green, and Blue, players can only start with the Electric-type Pikachu, which likewise has difficulty with the first Gym. The rival will take Oak's Eevee and evolve it into one of its three stone-based evolutions depending on the results of the player's battles against him.

025Pikachu Y.png

Gym Leaders

The eight Kanto Gym Leaders each specialize in a different type of Pokémon. Each gives the player a Badge and a TM after their defeat.

Indigo League
Gym Leader
Type Badge
タケシ Takeshi
Pewter City
Nibi City
Rock Boulder Badge.png
Boulder Badge
カスミ Kasumi
Cerulean City
Hanada City
Water Cascade Badge.png
Cascade Badge
Lt. Surge
マチス Matisse
Vermilion City
Kuchiba City
Electric Thunder Badge.png
Thunder Badge
エリカ Erika
Celadon City
Tamamushi City
Grass Rainbow Badge.png
Rainbow Badge
キョウ Kyou
Fuchsia City
Sekichiku City
Poison Soul Badge.png
Soul Badge
ナツメ Natsume
Saffron City
Yamabuki City
Psychic Marsh Badge.png
Marsh Badge
カツラ Katsura
Cinnabar Island
Guren Island
Fire Volcano Badge.png
Volcano Badge
サカキ Sakaki
Viridian City
Tokiwa City
Ground Earth Badge.png
Earth Badge


Generation I can be considered the template for every generation since. Many mainstays of the main series games were introduced in Generation I.

Some aspects introduced in this generation are found in every generation since, unless otherwise stated:

Some aspects introduced in this generation have been revised since:

  • In Generation I, the Bag had only 20 slots, and each item or stack of items occupied one slot. This forced the player to constantly store obsolete Key Items, TMs, and HMs in the Item Storage System in order to obtain new items. Later games would expand the Bag's storage space and provide additional Bag pockets to organize items. Starting in Generation IV, the Bag's storage is effectively limitless and can store all obtained items, obviating the need for the Item Storage System.
  • In Generations I and II, the player was unable to capture any more Pokémon if the current box in the Pokémon Storage System was full. Starting in Generation III, the player could use Poké Balls while the current box was full. If a wild Pokémon was captured in this circumstance, the next box would become the current box, and the captured Pokémon would be sent there.
  • In Generations I-IV, TMs are single-use while HMs can be used an unlimited number of times. Starting in Generation V, TMs have unlimited uses as well (outside of Pokémon Brilliant Diamond and Shining Pearl).
  • In the Generation I, the HMs Cut, Surf, and Strength are required for completion of the games. They may also be used to access optional areas. All Generation IIVI games also require some HMs for completion. Starting in Generation VII, HMs are not present at all, being replaced by the Poké RideSMUSUM/Secret TechniquesPE. In Pokémon Sword and Shield, there is nothing akin to HMs, except for the Galar Flying Taxi, a service where a cab flown by a Corviknight can bring the player anywhere with an open roof. In Pokémon Brilliant Diamond and Shining Pearl, HMs can be accessed through the Pokétch.
  • In Generations I-III, physical and special moves are determined by the move type. For instance, all Fire moves are special. Starting in Generation IV, physical and special moves are determined by the move itself, rather than their type.
  • Special is a stat that existed only in this generation. In Generation II, Special was split into Special Attack and Special Defense.

Battle system flaws

The battle system of the original games had some game balance issues, mainly due to the limited variety of Pokémon type combinations and movesets. Additionally, the behavior of multiple mechanics was inconsistent with their implementations in later games. Issues and mechanics that were fixed or altered in either the Pokémon Stadium series or in Generation II are listed below.

Balancing issues

  • Psychic-type Pokémon were strong because their moves were resisted only by other Psychic types and their only weakness was to the Bug type, of which there were only three damaging moves: Leech Life, Pin Missile, and Twineedle. Additionally, most of the Pokémon that learned these moves were part Poison and therefore weak to Psychic moves. Ghost-type moves, while meant to be super-effective, were completely ineffective against Psychic types due to what may be a programming bug. Even if this were to be disregarded, the only super-effective Ghost-type move would be Lick, whose power was only 20 at the time, and the only Ghost-type Pokémon that existed at the time were also part Poison-type.
  • Normal-type Pokémon were strong, as their only weakness was to the Fighting type. Most Fighting-type Pokémon couldn't learn many STAB moves other than Submission, which was inaccurate and dealt recoil damage, and they were difficult to use due to the presence of strong Psychic-type Pokémon. Normal-type Pokémon learn many moves of other types and could often use moves such as Earthquake or Blizzard to defeat Ghost-types and Rock-types that resisted their Normal-type moves.
  • The only damaging Dragon-type move was the set-damage Dragon Rage. This meant that Dragon-type Pokémon could never take advantage of STAB, and that the only moves that could hit them with super-effective damage were Ice-type moves.
  • The strongest Poison-type move was Sludge, which only had a base power of 65 and can only be learned by a few Poison-type Pokémon.
  • The Special stat represented both Special Attack and Special Defense, giving Pokémon with a high Special stat an edge in battle. For example, Venusaur had a base Special stat of 100, used Grass-type (considered "Special") moves, and was weak to mostly Special types.
  • Critical hit ratios were based on a Pokémon's base speed, allowing faster Pokémon to deal critical hits more frequently.

Battle glitches

Main article: List of battle glitches (Generation I)
  • Leech Seed and Toxic used the same damage counter, allowing Leech Seed to drain twice as much damage when a Pokémon was affected by both at the same time.
  • Focus Energy and Dire Hit divided the user's critical hit rate by 4 instead of multiplying it by 4.
  • Using Agility or Swords Dance while paralyzed or burned, respectively, would negate the status impairments from those effects and then double the enhanced stat.
  • If Hyper Beam knocked out a Pokémon or destroyed a substitute, the user would not need to recharge on the succeeding turn.
  • Selfdestruct and Explosion did not make the user faint if they destroyed a Substitute.
  • Although Rest removed status conditions, it would not alleviate the stat debuffs caused by a burn or paralysis.
  • If a Bide user was hit with a status move before its attacking turn, the damage dealt would equal that of the last attack used against it.
  • If a Pokémon's HP was 255 or 511 (or any number that leaves a remainder of 255 when divided by 256) points below its maximum, HP recovery moves like Recover and Softboiled would fail. This is because the game only checks the low byte of the 16-bit value.
  • When a Pokémon was hit by a move that did not deal neutral damage, the message that displayed would reflect only the matchup against one of the target's types.

Mechanical issues

  • Critical hits would ignore all stat changes, including increases to the attacking Pokémon's Attack or Special and decreases to the target's Defense or Special. This can result in a critical hit dealing less damage than an attack that does not land a critical hit.
  • Counter could be used in response to Guillotine or Horn Drill to instantly defeat an enemy Pokémon, even if the move hit the user's Substitute.
  • Moves lost their additional effect after they broke a substitute, preventing a Pokémon from fainting after using Explosion to break a substitute.
  • With the exception of Swift, every attack had at least a 1/256 chance of missing.
  • Wrap, Bind, Fire Spin, and Clamp immobilized the target for 2 to 5 turns as a side effect. If a Pokémon that used one of these moves switched out, the target would still be considered trapped during that turn.
  • Struggle was programmed with Normal-type offensive properties instead of being programmed to ignore type matchups, making it ineffective against Ghost types.
  • Waking up from sleep took a full turn.
  • Using Substitute while having 25% or less of one's maximum HP left would cause the user to faint.
  • As soon as Rage connected, the user would become unable to use any other move until it fainted. Subsequent uses of Rage would not consume PP, and if the user misses a subsequent Rage due to accuracy reduction or the target's increased evasion, the move's accuracy would become 1/256.
  • Multi-hit moves dealt the same amount of damage for each hit in a turn, meaning that if the first hit was a critical hit, the other hits would be critical hits as well.
  • In-game opponents had infinite PP, meaning they could use moves without limit.
  • In-game opponents with certain AI patterns will always use moves typed to be super effective against the target, even when those moves do not deal damage directly.

Kanto thematic motif

The first generation of Pokémon games dealt with genetics and engineering. Several Pokémon in this generation revolve around this theme: Eevee is capable of evolving into multiple forms due to its unstable DNA; Voltorb is the result of a Poké Ball experiment gone awry; and Porygon is a virtual reality Pokémon. These games also introduce three Fossils which can be resurrected into prehistoric Pokémon: Aerodactyl, Kabuto, and Omanyte. Finally, out of the four legendaries that appeared, the most powerful was man-made through genetic engineering: Mewtwo. The uncatchable Mythical Pokémon, Mew, also has the DNA of every Pokémon in existence.

Bill himself invented the sophisticated PC used in most regions and accidentally turned himself into a Pokémon. Ditto could also mimic the abilities and structure of any Pokémon it encountered, making it capable of breeding with most Pokémon from Generation II onwards. The Master Ball is the most powerful Poké Ball in the franchise, and was first engineered by Kanto scientists. With this generation being the very foundation of the Pokémon franchise, most successors have only expanded upon Kanto's basics.

Title screens

English title screens

Game Boy Color

Pokémon Red Pokémon Blue Pokémon Yellow
RedTitle GBC.png BlueTitle GBC.png YellowTitle.png

Super Game Boy

Pokémon Red Pokémon Blue Pokémon Yellow
RedTitle SGB.png BlueTitle SGB.png YellowTitle SGB.png

Japanese title screens

Game Boy Color

Pokémon Red Pokémon Green Pokémon Blue Pokémon Yellow
Japanese RedTitle GBC.png Japanese GreenTitle GBC.png Japanese BlueTitle GBC.png Japanese YellowTitle GBC.png

Super Game Boy

Pokémon Red Pokémon Green Pokémon Blue Pokémon Yellow
Japanese RedTitle SGB.png Japanese GreenTitle SGB.png Japanese BlueTitle SGB.png Japanese YellowTitle SGB.png


  • Of all the generations, Generation I introduced the most moves to the core series, with 165.
    • Generation I is the only generation in which the total number of moves is greater than the total number of Pokémon.
  • As far as release dates go, Generation I is the shortest generation in North America, partly due to the fact that Red and Blue were not released until 1998, while in Japan, they were released in 1996, and their successors, Gold and Silver, were released closer together, in 1999 in Japan and 2000 in North America. As the rest of the world's releases are more similar to the North American releases than the Japanese releases, it is also the shortest generation worldwide.
  • Prior to Generation VI, Generation I had the most extra space in the Pokémon Storage System if the player captures one of each Pokémon, with 240 spots available for 151 Pokémon, therefore leaving 89 extra spots.
  • Prior to Generation VIII, Generation I was the only generation not to feature the paired versions' mascots on the title screens, but instead included the first evolutionary stages of two first partner Pokémon.
  • Generation I is the only generation in which:
  • The Japanese releases of the Generation I games mark the only generation where two solitary core titles were released (Pokémon Blue and Pokémon Yellow).
  • Generation I is the only generation to have multiple pairs of remakes of its core series games.

Character names

  • Red, Blue, Daisy, Baoba, and Reina were introduced as unnamed characters in this generation.
  • The members of the Team Rocket were simply referred to as "Rocket", with no mention of the word "Grunt" in this generation.
  • Jessie and James appear as unnamed characters in Pokémon Yellow, although their names were already known from the anime.
  • In this generation, the individuals from each Trainer class such as Youngster, Lass, etc. are not named.
  • In the Japanese games of this generation, there is a shorter name for most Trainer classes that is seen when the respective Trainer is defeated in battle. For instance, the Youngster (たんパンこぞう Shorts Youngster) and Lass (ミニスカート Miniskirt) are abbreviated as たんパン Shorts and ミニスカ Miniski, respectively.


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