Pokémon Red and Blue/Version Differences

Silph Co's Other Branch
In the original Japanese games, the Scientist at 6F of Silph Co. refers to a supposed branch of the company in Ponaya Tunguska (Japanese: ポナヤツングスカ aka "Ponaya Tsungusuka"), likely a reference to the Podkamennaya Tunguska river in Russia. In the English versions, he instead refers to the branch as being in the real-life city of Tiksi, also in Russia.

It is not certain why the branch's location was changed, although it is likely that it was done to avoid further controversy with what is known as the Tunguska event, which occurred in the Podkamennaya Tunguska river in 1908.

Pokémon Mansion Diaries
In the original Japanese games, the diary entries on Cinnabar Island imply that one person was involved in the discovery and cloning of Mew as well as the subsequent creation of Mewtwo, as evidenced by the first-person singular personal pronoun わたし (watashi), the Japanese equivalent of the English first-person singular personal pronoun "I". Nowhere in the Japanese dialogue is the first personal plural personal pronoun わたしたち (watashi-tachi), the Japanese equivalent of the English first-person plural personal pronoun "we"; furthermore, in the Japanese February 6 diary entry, the sentence is worded in an impersonal manner.

In the English Red and Blue, all the diary entries except the July 5 one use the first-person plural personal pronoun "we" instead.

Chief Trainer Class
The Japanese name of the "Chief" Trainer class is シルフのチーフ (Shirufu no Chīfu), which translates to "Silph's Chief", implying that the player was originally meant to battle Silph Co.'s president.

Removed References
The German Rot und Blau removed references to real life. For example, the "Guyana, South America" line in the aforementioned July 5 diary entry was changed to "Dschungel tief im Niemandsland.", which translates back to English as "Jungle, deep in no man's land."

"¡El malvado (POKéMON) atacó!"
In the Spanish Rojo y Azul, encountering a Pokémon with a fishing rod returns the text "¡El malvado  atacó!". This is a presumable mistranslation, as the English text is "The hooked  attacked!", as in a Pokémon attached to the fishing rod. The problem with the Spanish translation lies in the word "malvado", which when translated back to English results in words such as "wicked" or "evil".

Raichu Trade


While this dialogue string is used for a Pokémon Lab trade by an NPC at Cinnabar Island in the English versions, an error persisted in the localization of the original Japanese Blue string:

The original trade involved the player trading a Kadabra for a Graveler. In regular gameplay, Kadabra evolves into Alakazam (and Graveler evolves into Golem) when traded for another Pokémon. However, Red and Blue involved the player trading a Raichu for an Electrode instead, much like in the Japanese Red and Green.

The changes in the Japanese Blue were not addressed, resulting in the odd message. During regular gameplay, it is impossible to evolve a Raichu.

TM acronym in the French versions


The acronym for Technical Machine (TM) in Rouge et Bleu is changed to CT, which is used correctly everywhere except one place: if the player exchanges a Lemonade for CT49 in the Rooftop Square of the Celadon Dept. Store, the text box says "TM49... TRIPLATTAQUE!"

Original Blizzard Freezing Chance Value
In the original Japanese releases, Blizzard has a 30.1% chance of freezing. The localizations, the Pokémon Stadium games, and the Japanese Yellow, when played in Colosseum 2 mode reduce this to 9.8%. The English Yellow instruction booklet mistakenly claims that Blizzard freezes less frequently in Colosseum 2 mode, which is only true in the Japanese releases since the value was reduced to 9.8% everywhere already in Red and Blue.

Original Thunderbolt Animation
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In the Japanese Red, Green, and Blue, using Thunderbolt results in more rapid screen flashes than in the localizations. This was changed possibly to remove the risk of seizures following Episode 38 of the original Pocket Monsters anime series, titled "でんのうせんしポリゴン" (Dennō Senshi Porygon, which translates to "Computer Warrior Porygon" or "Computer Soldier Porygon").

Minor Changes Between Red/Green and Blue

 * In the Japanese Red & Green, Missingno.'s Pokédex entry and its species value as the ??? don't appear upon capture, unlike the Japanese Blue.
 * In the Japanese Red, Green and Blue, withdrawing the Potion at the beginning of the game and using it without any Pokémon brings up the Pokémon menu, even though the player has no Pokémon, due to an oversight in the coding. This was patched in the Japanese Yellow and the localizations, which bring up the message "You don't have any/a Pokémon!" (Japanese: ポケモンが 1ぴきも いない!)

Oak's Parcel Glitch
In the Japanese releases, if the player already has two Pokémon (by evolving their starter Pokémon) before returning to Professor Oak to deliver Oak's Parcel, the game acts as if the player has already obtained the Pokédex even though s/he hasn't, thus it becomes impossible to progress through the game because the old man in Viridian City will only move after the player has actually obtained the Pokédex.

Select Button Glitch
SKmcDPtjx1I The localized Red and Blue patched an infamous oversight triggered by the Select button which allows the player to swap items with Pokémon by pressing Select on an item, closing the menu, opening the Pokémon party menu, and then pressing A.

This glitch results in many memory corruption glitches used by Japanese glitchers, the most popular being the "dokokashira door glitch", which allows the player to warp across the game by swapping the second item with the first Pokémon and beat the game within a few minutes. The glitch was patched by disabling the selected item flag in the programming when the menu is closed.

Viridian Old Man Glitch
One of the most famous glitches in Red and Blue, talking to the old man in Viridian City and watching his tutorial on catching Pokémon copied the player's name to an area normally used to determine wild Pokémon. If one were then to fly to Cinnabar Island and surf along the east coast, invalid Pokémon would appear corresponding to the player's name.

This glitch was partially fixed in the Spanish Rojo y Azul (and possibly other European versions as well): attempting to perform the glitch will simply result in wild Tentacool appearing, unless the walk-through-walls glitch is performed first.

This glitch resulted from a localization oversight. It did not occur in Japanese Red, Green, or Blue, where the Cinnabar Island coast triggers zero wild Pokémon.

Brock Skipping Glitch
In certain regional releases of Red and Blue, such as the English localization, it is possible to skip the battle against Brock by saving in the right spot and resetting to bypass the person blocking the path to Route 3. However, this was fixed in various European releases, such as the Spanish localization.

Man on the Roof Glitch


On Cinnabar Island, if the player doesn't have the Secret Key in the Bag and uses a Pokémon with Surf to surf on the east coast, returns to the shore while near the Gym and walks in front of the Gym's door, a sprite of an old man will appear on the roof of the Cinnabar Gym while the text box saying "The door is locked..." appears. After the text box disappears, the sprite will vanish.

There are other variations of this glitch, such as when pressing Start as soon as the player enters Nugget Bridge or Route 6. All variations were fixed in the Spanish localization and possibly other European releases.