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Pokémon Red and Blue
|Pokémon Red and Blue|
Also known as: Pocket Monsters: Red & Green (JP), Pocket Monsters: Blue (JP)
This game has unused areas.
This game has a notes page
This game has a bugs page
This game has a prerelease article
Pokémon Red and Blue, originally released in Japan as Pocket Monsters: Red and Green and later as Pocket Monsters: Blue, are the original Pokémon games that glued many children to their Game Boys as they began their quest to become the Pokémon champion.
Gotta catch 'em all!
- 1 Sub-Pages
- 2 Pokémon
- 3 Unused Game Mechanics
- 4 Unobtainable Items
- 5 Unused Trainer Classes
- 6 Unused Trainer Parties
- 7 Maps
- 8 Unused Song
- 9 Unused Functions
- 10 Unused Graphics
- 11 "Pocket Monsters!" Border Tiles
- 12 Miscellaneous Findings
| Translation Errors|
Text errors from when the game was translated from one language to another.
| Version Differences|
Differences in versions, as well as localization changes.
Early Pokédex Order
Unlike later games, the internal Pokémon species table is far from sorted: they aren't grouped by their evolutionary families nor any other reasonable order. For example, index numbers 0x01, 0x02, and 0x03 are Rhydon, Kangaskhan, and Nidoran♂. This is likely an early Pokédex order, or even the order in which the Pokémon were originally added to the game.
One special episode of Game Center CX features an interview with Pokémon creator Satoshi Tajiri. During the interview, a possible early design document or proposal for the games is shown complete with close-up shots of three different Pokémon: Nidoking, Slowbro, and Kadabra. The documents depicted the Pokémon sprites from Red and Green as well as their names and Pokédex numbers. Interestingly, the numbers do not match up with the final Pokédex order but rather the internal species table, placing Nidoking at 0x07, Slowbro at 0x08, and Kadabra at 0x26. It can also be assumed that those screens come from a very early version of the in-game Pokédex function, considering the layout of the screen and the faintly visible Super Game Boy border.
Also of note is Nidoking's early name which, rather than the final ニドキング (Nidokingu), is マイコー♂ (Maiko♂).In addition, the species table has 190 entries, 39 of which are completely blank and result in the game loading MissingNo. (see below) instead. Words from Shigeki Morimoto have supported that there were once 190 Pokémon planned for inclusion in the games.
Arguably the most (in)famous glitch/leftover in any game, MissingNo., short for "Missing Number", is used to fill the 39 empty slots of the 190-slot Pokémon species data table. The glitch was made famous when players discovered a way to encounter it by exploiting a programming oversight in said data table for helpful side effects. The land/water border tiles on the east coast of Seafoam and Cinnabar Islands are set to generate random wild Pokémon encounters from the current location (as grass tiles do) rather than with water Pokémon. Since these areas do not have random wild Pokémon encounter data, the data from the previous area is left in memory. In the Japanese version, its name is けつばん (Ketsuban), which literally translates into "missing number."
The aforementioned Pokémon species table has 39 entries which give MissingNo. a Pokédex number of #000. As the base stats are ordered by Pokédex number as opposed to index number, this results in all the 39 MissingNo. copies sharing the same type (Bird/Normal), stats, start moves, graphics, etc. None of this data is actually valid; the game reads data that is stored far outside the base stats table and is actually used to define the parties of trainers. In the Japanese Blue, MissingNo. points to data that defines it as a ??? Pokémon, with a height of 1.0 m (3.3 ft) and 10.0 kg (22.1 lb), as well as a filler Pokédex entry saying 「コメント さくせいちゅう」 "Komento sakusei-chū", which translates into "Comment to be written". This information was not translated in the English localization and hence displays the erroneous values of 10.0 ft (3.1 m) for the height and 3507.2 lb (1590.8 kg) for the weight when its Pokédex entry is viewed.
Old Man Glitch
During the old man's Pokémon-catching tutorial in Viridian City, the player's name is changed to "OLD MAN". The original name is copied into the wild Pokémon encounter table for temporary storage. As soon as the player enters an area with wild Pokémon encounters, the table will be repopulated, so this normally has no effect on the game. However, taking advantage of the incorrect water tile assignment allows players to encounter wild Pokémon while the encounter table still contains the player's name. The letters of the name then define which Pokémon will appear and at which levels; several letters correspond to invalid IDs, leading to encounters with MissingNo., 'M, or glitched Trainers at impossibly high levels. In the Japanese version this does not work, and no encounters of any kind will occur on the affected tiles.
Contributing to MissingNo.'s fame is the item duplication glitch. Any time the player encounters MissingNo., 'M, or any other glitch Pokémon with Pokédex number 000, the game attempts to set the "Pokémon has been seen" flag for that Pokémon in the Pokédex. Due to an integer underflow when calculating the address of this flag, it instead sets the highest bit of the quantity of the sixth item in the player's Bag, effectively adding 128 to it. If you catch it, the sixth item duplicates again (assuming it's been reduced to less than 128).
The glitch Pokémon 'M (actual name consisting of corrupted graphics with 'M in the middle) is often confused with MissingNo., as they are both commonly found using the Old Man glitch and both have the Pokédex number 000, giving them the same in-battle sprite and base stats, and causing the item duplication glitch. However, 'M is not pulled from unused Pokémon data like MissingNo. but from other data located after the Pokémon data in ROM instead. Its similarities to MissingNo. are coincidental.
Most variations of MissingNo. have similar appearances to the screenshot above, but it can also assume the sprite of one of the fossils in the Pewter City museum or a Pokémon Tower ghost depending on various factors. (It should be noted that in the Japanese versions of the games, a ghost MissingNo. is referred to not as けつばん but by the otherwise unused string of "ゴースト" - distinct from actual Pokémon Tower ghosts, which are called "ゆうれい".) Each MissingNo. also has a separate cry. Most of these are simply set to three zeros, resulting in its cry sounding similar to Nidorin♂'s cry, however there are a few unique ones (see here). Each individual MissingNo. entry has a unique, empty move-learning and evolution table, further suggesting that these slots belonged to deleted Pokémon. Additionally, MissingNo.'s name is repeated 39 times in the ROM, once for each entry.
Unused Game Mechanics
Bird TypePokémon Gold and Silver.
Extra Field Move
In the list of field moves, there is an unused entry between Fly and Surf. It points to an empty string in the field move name table. It has a move ID of 0xB4, although the highest valid move ID is 0xA5, suggesting that there were moves removed before the games were released. Its position in the list of field moves, between two HMs (all HMs are in order) suggest this may have once been an HM.At offset 0x80096 is the unused text string "Ground rose up somewhere!", which is located near the string used when using Strength. It has been suggested that it was originally intended to be used for a field move.
"NORTH/WEST", "NORTH/EAST", and "SOUTH/EAST"
In addition to the normal options such as "YES/NO" and "HEAL/CANCEL", additional options "NORTH/WEST" (Japanese: きた/にし), "NORTH/EAST" (Japanese: きた/ひがし) and "SOUTH/EAST" (Japanese: みなみ/ひがし) are present but never used. "NORTH" and "EAST", while referenced in the Safari Zone, are found within strings of text rather than as options.NORTH/WEST can be seen with GameShark code 01012CD1, NORTH/EAST can be seen with GameShark code 01042CD1 and SOUTH/EAST can be seen with GameShark code 01022CD1.
Default Total PP of StruggleStruggle is a move which cannot be learned during regular gameplay. It is only used when the user's Pokémon attempts to attack but has no available PP for any move left (note that in-game Trainers cannot run out of PP in Generation I). Regardless, the default total PP data for Struggle is set to be 10, though there is a special handler for Struggle such that its remaining PP does not decrement since it is never supposed to be an actual move in a Pokémon's moveset.
The default total PP for Struggle was changed to 1 in generation II, and remains that way in all the main series handheld Pokémon games as of Generation V.
Unused Battle AIThere is data for unused battle AI routines which are normally never executed by any Trainer class, including "use X Accuracy", "use Dire Hit", and "use X Special".
Dragon Type is Super Effective against Itself
The Dragon type does super-effective damage to itself in Generation I, just as it does in every subsequent generation. However, the only Dragon-type move in Generation I is Dragon Rage, which does a set regular damage of 40 HP, and hence this behavior is never seen in regular gameplay during this generation.
Unused Move Effects
There are a handful of effects in English Red and Blue which aren't used by any valid move, although some of these are used by the TM(xx) and HM(xx) glitch moves. Note that in the Japanese versions, effect 23 (30.1% freeze chance) was used because the effect was assigned to Blizzard (see here).
|01||Puts enemy to Sleep.|
|0C||Raises Speed by 1 stage.|
|0E||Raises Accuracy by 1 stage.|
|15||Lowers Special by 1 stage.|
|17||Lowers Evasion by 1 stage.|
|1E||Attacks for 2-5 turns.|
|23||30.1% chance of freezing the opponent.*|
|36||Raises Accuracy by 2 stages. (probability=hit chance)|
|37||Raises Evasion by 2 stages. (probability=hit chance)|
|3A||Lowers Attack by 2 stages. (probability=hit chance)|
|3C||Lowers Speed by 2 stages. (probability=hit chance)|
|3D||Lowers Special by 2 stages. (probability=hit chance)|
|3E||Lowers Accuracy by 2 stages. (probability=hit chance)|
|3F||Lowers Evasion by 2 stages. (probability=hit chance)|
|48||10.2% chance of lowering Accuracy by 1 stage.|
|49||10.2% chance of lowering Evasion by 1 stage.|
|4A||10.2% chance of lowering a non-existent glitch stat by 1 stage, which effectively does nothing.|
|4B||10.2% chance of lowering a non-existent glitch stat by 1 stage, which effectively does nothing.|
Butterfree for Beedrill in-game Trade
Replace video with a screenshot if necessary.
There is an unused in-game trade in which the player would trade a Butterfree for a Beedrill, which was carried over from the Japanese Red and Green. In those versions, the traded Beedrill was originally nicknamed ピピん (Pipin); however, in the Japanese Blue (which the international Red and Blue are mainly based upon), its nickname was changed to チクチク (Chikuchiku).
As such, there is unused text in the English Red and Blue for a Beedrill nicknamed "CHIKUCHIKU".
The trade is actually fully functional and can be accessed with a GameShark code. Once entered, use the first glitch item in your pack. Due note that the code has the side effects of changing your item pack items in all versions and data from DA47-DA49 (wNumSafariBalls wDayCareInUse, wDayCareMonName) (Red), or wild Pokémon data (Japanese Blue, Green).
|English Red or Blue version||Japanese Blue version||Japanese Green 1.0 version|
01C347DA 012248DA 01D349DA 016A1ED3 013E22D3 010223D3 01EA24D3 013D25D3 01CD26D3 013E27D3 015428D3 01CD29D3 016D2AD3 013E2BD3 01C32CD3 01D72DD3 01242ED3 01C92FD3
01C306D8 01A607D8 01D208D8 017BA2D2 0150B4C3 013EA6D2 0102A7D2 01EAA8D2 013DA9D2 01CDAAD2 013EABD2 0154ACD2 01CDADD2 01B1AED2 013EAFD2 01C3B0D2 01B7B1D2 0124B2D2 01C9B3D2
01C306D8 01A607D8 01D208D8 017BA2D2 013EA6D2 0102A7D2 01EAA8D2 013DA9D2 01CDAAD2 013EABD2 0154ACD2 01CDADD2 019DAED2 013EAFD2 01C3B0D2 016AB1D2 010FB2D2 01C9B3D2
There are several unobtainable items in the games. These remain present and unaltered in Yellow.
|00||Appears as a glitch item if forced to load. It is called "!j" in Red and Blue and "x" in Yellow.|
|07||?????||0||0||This item's name was dummied out. It allows you to surf without requiring a Pokémon or the necessary badge. It can also be used on Cycling Road without the usual "Cycling is fun! Forget SURFing!" message. Additionally, while using this item, the music of the area updates normally. Attempting to use this item while facing land as you are surfing glitches the item name tile graphics and causes the game to freeze. Internally, it implements the effect of the Surf HM, unlike other HM moves, though it is similar to the out-of-battle effect of Dig, which is handled by using an Escape Rope.|
|08||Safari Ball||1000||500||While used, this item is unobtainable via normal means. Unlike in later generations, it is classified as a key item in Generation I.|
|09||Pokédex||0||While used, this item is unobtainable via normal means. It can be used both during and outside of battle, opening the Pokédex. However, using it in battle causes the VRAM to load the overworld tileset, and turns the HP bar into letters.|
|15||BoulderBadge||0||0||When used in battle, this item behaves like the Throw Bait function in the Safari Zone. When used in the overworld, it changes the background music to a single channel of the song Guide. When used in a dungeon or cave, it changes the background music to a single channel of the song Title Screen. This is because the function is attempting to load the "throw Bait or Rock" sound effect, but instead refers to the wrong soundbank.|
|16||CascadeBadge||0||0||When used in battle, this item behaves like the Throw Rock function in the Safari Zone. When used in the overworld, it changes the background music to a single channel of the song Guide. When used in a dungeon or cave, it changes the background music to a single channel of the song Title Screen. This is because the function is attempting to load the "throw Bait or Rock" sound effect, but instead refers to the wrong soundbank.|
|17||ThunderBadge||0||0||Attempting to use this item displays Professor Oak's "This isn't the time to use that!" message.|
|18||RainbowBadge||0||0||Attempting to use this item displays Professor Oak's "This isn't the time to use that!" message.|
|19||SoulBadge||0||0||Attempting to use this item displays Professor Oak's "This isn't the time to use that!" message.|
|1A||MarshBadge||0||0||Attempting to use this item displays Professor Oak's "This isn't the time to use that!" message.|
|1B||VolcanoBadge||0||0||Attempting to use this item displays Professor Oak's "This isn't the time to use that!" message.|
|1C||EarthBadge||0||0||Attempting to use this item displays Professor Oak's "This isn't the time to use that!" message.|
|2C||?????||0||0||This item's name was dummied out. Attempting to use it displays Professor Oak's "This isn't the time to use that!" message.|
|32||PP Up||9800||4900||This duplicate PP Up uses index number 0x32, while the actual PP Up is at 0x4F. Unlike the regular PP Up, which has a buy and sell price of ¥0, this version is worth significantly more.|
|3B||Coin||10||5||This item can be stacked in the inventory, but cannot be stored in a Coin Case, and attempting to use it displays Professor Oak's "This isn't the time to use that!" message.|
Elevator Floor Names
Following the list of item names, at offset 0x4A63 in the English games and 0x45B5 in the Japanese, are a list of the floor names used by elevators. These are stored in the same format as the item names. As a result, they can be loaded as items, but lack valid effects and may freeze the game when used.
Additionally, there are several curious unused text strings at offset 0x45F5 in the Japanese Red and Green. The same data can also be found at offset 0x4A92 in the English games. However, in the English games, these strings display as gibberish, as the character table is incompatible between the Japanese and English releases.
Curiously, the badge names are written バッヂ (baddzi) instead of バッジ (bajji), as in the final game.
|62||かみなりバッヂ||Thunder Badge||The Japanese name for the Thunder Badge is actually the Orange Badge.|
|6A||ゴールドバッヂ||Gold Badge||The Japanese name for the Marsh Badge is the Gold Badge.|
The last entry, "Excellent", is unusual in that it is not terminated by 0x50.
It appears that the Hidden Machines were once classed as Technical Machines, themselves. Unlike the corresponding HMs, these TMs can be stacked in the inventory, as well as sold at PokéMarts.
|FB||TM51||3000||1500||This item functions like HM01 (Cut).|
|FC||TM52||14000||7000||This item functions like HM02 (Fly). Its sell price displays as a glitched tile followed by three zeroes.|
|FD||TM53||0||0||This item functions like HM03 (Surf).|
|FE||TM54||8000||4000||This item functions like HM04 (Strength).|
|FF||TM55||4000||2000||This item functions like HM05 (Flash). It is used as the game's Cancel function, displaying the text "Cancel" and hiding items below it.|
Unused Coin Drop
The hidden coin item on the ground directly three squares above the top-left slot machine on the cluster of machines that is the second from the east side is supposed to give you 40 coins. However, due to a typo in the routine that handles picking up hidden coins, only 20 coins are found instead.
Unused Trainer Classes
Triggered by an hexadecimal identifier of 0xE3. It actually has no sprite, but uses the Scientist Trainer class sprite because its identifier is directly before it (0xE4). No rosters appear to be defined, meaning 'its first roster' is the first Scientist's roster. The Chief has not been found to give any valid victory speeches when defeated. Despite this, he is still mentioned in-game by a Team Rocket Grunt in one of the houses near the hotel in Celadon City, whose dialogue is "CHIEF! We just shipped 2000 POKéMON as slot prizes!"Interestingly, 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". This implies that the player was originally meant to battle Silph Co.'s president.
A battle with Professor Oak is programmed in, although he never actually battles the player during regular gameplay. The battle can be triggered with GameShark code 01E2D8CF (where the level of what would be a wild Pokémon corresponds with the roster value), or by using one of various glitches in the game. His name appears as "PROF.OAK" (Japanese: "オーキドせんせい" aka "Ōkido-sensei", rather than the normal "オーキドはかせ" aka "Ōkido-hakase").
Oak is programmed with three different teams, each consisting of a Level 66 Tauros, a Level 67 Exeggutor, a Level 68 Arcanine, and a Level 70 Gyarados. His fourth Pokémon is Level 69 and is either a Venusaur, Blastoise, or Charizard. It is assumed the game would choose the team with the final evolution of the starter Pokémon that neither the player nor the rival chose. Additionally, based on this team and their levels, it's likely he was supposed to appear at the very end, perhaps even after the final rival battle at Indigo Plateau. When defeated and counting the fact that Professor Oak used one of the valid rosters mentioned above, he will give whatever dialog that the Trainer you used to fight him says when defeated. This means that he has no real "lost battle" dialogues of his own programmed in.
It is possible to battle him using the Ditto glitch (an extended version of the Mew glitch) with the last Special stat in memory as 226. He can be encountered (though without his appropriate roster) as a glitch Trainer while doing the Old Man glitch and having the MN symbol in the third, fifth, or seventh slots of the player's name. Another way of battling him is this select button glitch in Japanese Red, Green and Blue.The data for this battle remains present in Yellow. The concept of battling a Pokémon professor would later be reused in Pokémon X and Y.
Unused Trainer Parties
Several trainer parties that are never referred to by trainer objects exist in the game. Below is a list of the parties' Pokémon and corresponding party level and trainer type (which can be determined by the pointers to the trainer classes' rosters).
|Trainer class||Roster ID||Party LV||Pokémon|
|Youngster||0D||L17||Spearow, Rattata, Rattata, Spearow|
|Bug Catcher||0C||L18||Metapod, Caterpie, Venonat|
|Jr. Trainer♂||06||L18||Diglett, Diglett, Sandshrew|
|Super Nerd||06||L22||Koffing, Magnemite, Weezing|
|Super Nerd||07||L20||Magnemite, Magnemite, Koffing, Magnemite|
|Super Nerd||08||L24||Magnemite, Voltorb|
|Burglar||03||L28||Vulpix, Charmander, Ponyta|
|Gambler||06||L22||Onix, Geodude, Graveler|
|Beauty||0B||L33||Weepinbell, Bellsprout, Weepinbell|
|Tamer||06||L42||Rhyhorn, Primeape, Arbok, Tauros|
|Bird Keeper||0C||L39||Pidgeotto, Pidgeotto, Pidgey, Pidgeotto|
|Bird Keeper||0D||L42||Farfetch'd, Fearow|
|Cooltrainer♂||06||L44||Ivysaur, Wartortle, Charmeleon|
|Cooltrainer♀||08||L43||Persian, Ninetales, Raichu|
There are 22 deleted map locations, including a tentative unused town with its own Fly flag. They have music values and pointers to header data, but they all point to headers of existing maps, though it looks for them in the entirely wrong banks. Headers and map data may have been shuffled around during development, since several maps attempt to use headers for Lance's room in the Elite Four. Due to having no data and most likely trying to read the header from the wrong bank, all of these freeze the game when accessed.
- An unused map likely to be a town, with identifier 0x0B. It uses Saffron City's header, but loads from bank 0x01, which has no map headers at all. See the section below.
- 11 deleted maps using the header for Lance's room, with identifiers 0x69-0x6B, 0x6D-0x70, and 0x72-0x75. They all load from bank 0x1D, where all the other Elite Four rooms are, but Lance's room is in 0x16.
- 3 deleted maps using the header for the Rocket HQ Elevator, with identifiers 0xCC-0xCE. They load from bank 0x01, which has no map headers.
- A deleted map using the header for Route 16's gate, with identifier 0xE7. They also load from bank 0x01.
- 6 deleted maps using the header from Silph Co.'s second floor, with identifiers 0xED-0xEE and 0xF1-0xF4. They load from bank 0x11, but the correct header should be 0x16.
Map 0x0B is stored alongside city/town maps (0x00-0x0A; routes start with Route 1 at map 0x0C) and has Town Map location data as a town (not as a route) north of Indigo Plateau, since an unused flag when checked allows the player to Fly to it. It erroneously appears north of Indigo Plateau because its coordinates are undefined, leading the game to fallback to coordinates (0,0). The relevant Town Map name is also presumably undefined and shares its name with prefix 0x00: Pallet Town. Additionally, no Pokémon appear in map 0x0B. From this, it can reasonably be concluded that there was at one point another town in that location, removed from the final releases.
Since it would be unreasonable to end up on the fifth floor of somewhere from Celadon City and not the first floor, it may suggest that map 136 was altered at some point in the game's development. Further supporting this theory, the other floors (in order) for the Celadon Department Store have index numbers 122-125 respectively. The fifth floor (map 136) does not follow this pattern.
Exit location data exists for the map (the exit point index number is 08).You can create a door to access the warp with the GameShark code 017C72C8. You can appear where the warp is by using the GameShark codes 0108B5D3 0108B1D3, entering a certain map in Celadon City (such as the Pokémon Center) and exiting.
Unused Alternative Maps
For unknown reasons, complete maps exist within the games which correspond to real locations, but these corresponding maps use different theme music for what was actually used for the same location in the final releases. These maps can be accessed via the map location modifier code 01XX5ED3.
|Location||Used map identifier||Corresponding unused map identifier||Music of used map||Music of the corresponding unused map|
|House robbed by a Team Rocket Grunt in Cerulean City||0x3E||0x45||Cerulean City Theme||Caves of Mt. Moon|
|Underground Path entrance (Route 6)||0x4A||0x4B||Pewter City Theme||Vermillion City Theme|
|PokéMart in Cinnabar Island||0xAC||0xAD||Pokémon Center||Cinnabar Island Theme|
Duplicate Diglett's Cave Map Data
There are two copies of the map data for Diglett's Cave in the English Red and Blue (and probably other localizations too). In these versions, the maps are at ROM offsets 0x60258 and 0x61F86.
Hidden Items in Unused Maps/Misplaced in Maps
Show where the coordinates are located on the map (since it's a small enough map, it should be okay).
In certain areas around the Safari Zone entrance, using your Itemfinder causes it to tell you there is a hidden item nearby, which is unobtainable. The item is a Nugget, located at the coordinates (10,1). This suggests that the map was changed during development without the hidden item being removed, as hidden item data is separate from other map data.
There are also coordinates for a hidden Max Elixer at coordinates (14,11) of unused map 0x6F, for which there is no map data.
Pokémon Center data in other maps
Pokémon Center data including triggers for PCs can be found in maps that are not used as Pokémon Centers in Red and Blue. As there is no PC sprite, the PCs are invisible. All of the hidden PC triggers were removed in Yellow.
The Celadon Hotel has an invisible PC in the same position as a Pokémon Center.
Safari Zone rest housesUnused code suggests that 3 of the rest houses in the Safari Zone, specifically maps DF, E0 and E1 were intended to function as Pokémon Centers. Each map has a trigger for an invisible PC in the same position as a Pokémon Center. Additionally, when healing at a Pokémon Center, the game saves your current location as the place to return to when using e.g. Teleport. The code checks if you're in one of the rest houses, and if so will not save your location.
|Game Genie |
Red and Blue both contain a short unused song with no defined pointers. As it only has two channels, with the octaves set too high and one channel that goes off-sync with the rest of the music, the song appears to be incomplete. The song is defined in the ROM with a relatively high tempo. The addresses for the two channels can be heard and are stored in the ROM at offsets 0xA913 and 0xA9CF, respectively. The restored version of the track gives an idea of how the song should have been:
The song can be patched to Pallet Town by changing offsets 0x822F to 13, 0x8230 to 69, 0x8232 to CF, 0x8233 to 69, 0x8235 to 6F and 0x8236 to 6A. Game Genie equivalent at the left.
Unused functions and subroutines in the program.
Setting bit 1 of RAM address D732 enables some debug features:
- When starting a new game, most of Oak's intro speech is skipped, including the player and rival name selections. Their names are set to "NINTEN" and "SONY" respectively.
- In the original Red and Green, the player is named やまぐち (Yamaguchi, named after Wataru Yamaguchi, who is listed in the game credits under Special Thanks), and the rival is named いしはら (Ishihara, named after Pokémon developer Tsunekazu Ishihara).
- In the Japanese Blue, the player is named ゲーフリ (Gēfuri, an abbreviation of "Game Freak"), and the rival is named クリチャ (Kuricha (creature), a reference to Creatures Inc.)
- When starting a new game, the player starts outside their house, rather than in their bedroom.
- Holding B prevents wild Pokémon encounters.
Error CodesTrainer-Fly glitch. For example, fleeing from the long-range Trainer on Route 6, re-enabling the ability to use the start menu with a Trainer in a location other than Route 6 and returning to Route 6 after reading the PokéMart sign in Vermilion City will bring up a '9 ERROR.' as shown in the picture on the left. This is because the PokéMart sign has a text identifier of 09, stored in the memory address CF13, so the game attempts to load the last text box ID in memory. The corresponding text for Route 6 doesn't exist and is presumably just a single 00 character, so the game prints a '9 ERROR.' The PokéMart sign in Yellow has a text identifier of 0B, which coincidentally does not give an error message, though the 'VERMILION CITY The Port of Exquisite Sunsets' sign has an identifier of 08 and brings up a '8 ERROR.' upon returning to Route 6.
Gift Pokémon Function
In Japanese Red and Green, an unused function exists at ROM addresses 01:645C (Red v1.0), 01:645D (Green v1.0), 01:6401 (Red v1.1), or 01:6402 (Green v1.1), that adds three Pokémon to the player's party:
- Exeggutor, level 90
- Ekans, level 90
- Rhydon, level 5
In Japanese Blue, the function is at 01:656F and adds three Pokémon to the player's party:
- Exeggutor, level 90
- Chansey, level 100
- Rhydon, level 5(Source: Glitch City Laboratories Forums)
In the English Red and Blue, the function is at at ROM address 01:64CA and adds five Pokémon to the player's party:
- Exeggutor, level 90
- Mew, level 20
- Jolteon, level 56
- Dugtrio, level 56
- Articuno, level 57
In an interview with Pokémon developer Tsunekazu Ishihara, he states that Exeggutor is his favorite Pokémon, since he used it while debugging the game. This may explain the first entry in the list.
Unused "Battle Test" Function
Check whether the code exists in non-English translations. It seems to have been removed in Yellow, but it could still exist in an altered form.
This code was likely intended for debugging purposes. It can be accessed by running the code at 01:4DA6. This requires a bank switch, which is possible via the bank switch function at $35D6 (see here for the location in other regions/revisions), which sets the bank to what register c is, and jumps to hl.
It sets the badges value to $80 (effectively giving you the Earth Badge and no other badges), sets your current location to Pallet Town (though you can't see it), removes your current party Pokémon, and prompts you to nickname a level 20 Rhydon. Whether you give it a nickname or not, it will start a battle against another level 20 Rhydon. All four of your available moves only act like Pound, though this doesn't apply to the opposing Rhydon. After the battle (regardless of the outcome), the nickname prompt appears again and the entire process repeats.The code exists in Pokémon Red and Green too, at 01:4B8D, where it seems to work the same.
Game Boy Color detection
At the very beginning of the program (ROM address 0150), the game checks if it's running on Game Boy Color, and stores the result of this check at RAM address CF1A. However, the check stores zero in both cases:
cp a,$11 ;GBC can be detected by value of A register at boot jr z, .gbc xor a, a ;If not GBC, A = 0 jr .ok .gbc: ld a, 0 ;If GBC, A = 0 .ok: ld [$CF1A], a
The use of two different methods to set A=0 (single-byte
xor a,a instruction vs the two-byte
ld a,0) suggest that this check may have been quickly patched out. In any case, a few instructions later the init process clears all memory, so this flag gets reset either way.
If this flag is set, the game loads a set of monochrome palettes and skips loading Super Gameboy features, so it looks the same as it would on a regular Game Boy.
Figure out what the other missing blocks in tilesets 03, 06, 0B, 0C, 0D, and 10 are.
Outside the S.S. Anne
A sign is present in this tilemap but is unused, other maps do use the graphic though.
Out Of View Graphics
There is a truck and boxes on the map that cannot be seen normally at the S.S. Anne dock.
It is possible to see them using tricks, however:
- You must be one block above and one block to the left of the guy who checks the ship's tickets. Now walk one block to the right and then press start immediately after you come to a stop. Now save and restart your game, your character should be facing right. Now use the HM Surf and you will surf onto the ticket checker; press Down to bypass him.
- You acquire a Pokémon with the HM Cut through a trade. This bypasses getting the HM on the ship which as a result makes the ship leave. You then obtain the HM Surf later and you can now surf to see the truck.
- Acquire the HM on the S.S. Anne and lose to a Pokémon battle. Come back to the ship once you can use surf.
Despite rumors, the truck is only decoration and does not have anything hidden around or under it, save for a Lava Cookie in the GBA remakes.
The cave tileset contains some graphics that resemble the standard rock graphics, but they appear to be shinier and transparent, suggesting that it might be ice.
The underground tunnel appears to be missing some graphics for the wall.
Below is a recreation of how the tiles may have been arranged. It appears it was intended to have some sort of lighting fixture on the wall.
Walking Elite Four Sprites
The Elite Four have walking sprites, but these are never seen in-game since they stand in one position and don't move. Colorized versions of Lance's walking sprites were used in Pokémon Gold and Silver.
"Pocket Monsters!" Border Tiles
Game Genie codes to restore the original logos.
Using a walk-through-walls cheat to enter the Pokémon exhibits outside of the Safari Zone entrance and attempting to talk to the Pokémon in them reveals that they have placeholder dialogue programmed in, most likely in order to prevent crashing. This dialogue can also be seen when attempting to talk to a trainer in the Cable Club.
Fossil Pokémon Sign
This sign is supposed to show an empty Pokédex entry for the fossil Pokémon which were not chosen in Mt. Moon. However, if the event is skipped by using a walk-through-walls cheat or warp glitch, the sign will instead display a placeholder consisting in suspension points, which is likely programmed in order to prevent crashing like the other one.