|This article is a summary page for different variations of a glitches, etc. when talked about as a whole.|
In the first generation of handheld Pokémon games, a total of three complete, but unused maps exist within the game, which are slightly different versions of other map locations such as the PokéMart within Cinnibar Island.
The alternative map locations are almost identical to the respective and final map location in the sense that they are visually the same, share the same Town Map name, and have NPCs whom share the same map events.
For unknown reasons the default music between these maps are different. For example, the default music for the burgled house in Cerulean City is Cerulean City's theme in the final version, although the alternative and unused version is the same apart from the fact that it plays Mt Moon's theme instead.
The dokokashira door glitch can be used in Pokémon Red, Green, and Pokémon Blue (Japanese) to travel to maps 0x45 (dec:69), 0x4B (dec:75) or 0xAD (dec:173). Below is a table comparing the details of the unused alternative maps when compared to their corresponding final map.
One means of accessing the map is through the GameShark code 01xxE4D2 (01xx65D3 in Pokémon Red and Blue, 01xx64D3 in Pokémon Yellow) where xx is the map identifier in hexadecimal — enter a building such as your house in Pallet Town (certain maps won't work for this or will have you land you in a Glitch City instead) and then step out to warp. xx can be changed back to 00 to be able to leave the house.
Additionally, players may enter the Gameshark code 01xxDDD2 (01xx5ED3 in Pokémon Red and Blue) and activate it when entering through a door, or immediately after using the move Fly.
In the expanded items pack in English Pokémon Red, Blue, and Yellow, the address changed in the first GameShark code (D365/4) can be adjusted by modifying the quantity of item 36; where the item is usually a "j." (Red/Blue) or "×" (Yellow), or a Master Ball (an Ultra Ball x0  is normally four slots above it and can be swapped into item 36 to access every map location).