Dokokashira door glitch

The Dokokashira door glitch (Japanese: どこかしらドアバグ  door bug) is a Select glitch in Generation I, which exists in as well as the Japanese Pokémon Blue.

It is similar to tweaking and the surf glitch in Generation IV. It can be used to enter the Hall of Fame without battling the Elite Four or the. It is still possible to trigger this glitch in the international releases of - however, it will have different effects from the Japanese releases, and it will not cause the player to warp.

Execution
From a new game, the player obtains at least two items, with Oak's Parcel in the second slot. The bag should then be opened and the player should press the Select button on Oak's Parcel, then select Cancel twice. This will cause the cursor to stay white. A wild should be initiated and then the player should open the Pokémon menu and press A while over first Pokémon, thus swapping it with a 'M (FF). The player should open the fight menu, to prevent the game from managing as if there are no Pokémon on the field when the battle ends and then run away.

From now on, the glitch should be active. Some of its effects are undesirable, such as slight graphical errors on the main map interface; however, one of the more useful effects will ensure that the warp location of the next door the player walks through is relevant to the amount of extra steps he or she takes, with the warp location changing every extra four steps.

Explanation
The Dokokashira door glitch takes advantage of the fact that in Pokémon Red, Green and Japanese Blue, the player is able to switch the slots of items as well as Pokémon. However, an oversight of this feature was that if the player were to press the Select button on the items screen and then exit out of the menu, the game will still remember the position where Select button was held down previously.

When the player switches the second item in his or her Bag with his or her first Pokémon, it will force the game to switch the second Pokémon (which is nonexistent) with the first one. In this particular early-game scenario, it switches the end of list marker to the first position. This confuses the subroutine which applies the poison damage in the overworld, causing it to check Pokémon beyond the sixth slot for poison damage, decrementing massive amounts of RAM addresses while thinking they are party Pokémon's health points.

Path calculation
An equation from Glitch City Laboratories allows calculation of the map location the player will appear after walking through the doors affected by this glitch.

It is: WarpID = k-(Steps/4), where "WarpID" is the map identifier that the player is warped to, "Steps" are the amount of steps walked by the player and "k" is a constant, depending on the player's map location. The equation is not applicable if its right side falls below zero.

Only one of the entrances will warp the player, depending on the map. If the player enters or exits the map through any of the non-warping entrances, the amount of "steps walked" will be reset to 0 and the map constant will be refreshed.

Constants
Below is a list of constants (k), used in the path calculation equation above. Warp location is the entrance which will cause the player to warp to the map specified by the equation.

Hall of Fame warp
To warp to the Hall of Fame, players must complete the above method, then follow this method. From the spot the wild Pokémon was battled, the player should take around 83 steps, landing the last step on the door of 's house in Pallet Town. The player will warp to, from where the player should walk to Celadon City, enter the Pokémon Center, immediately exit it, then enter the Celadon Department Store through the right entrance in the most linear way possible. The player will warp to Lance's room, where the player should proceed through the back door. If the player talks to Lance, the game will crash. The player should then walk past, into the next room. The player will now be in the Hall of Fame, which counts as the player defeating the Pokémon League and will display the credits. Alternatively, entering the Celadon Condominiums building instead of the Pokémon Center will warp the player right to the Hall of Fame room after entering the Celadon Department Store, although with glitchy graphics.

Unused map 1 warp
An alternative version of the entrance to Underground Path, with a default music theme of Vermilion City, instead of its final Pewter City theme. By traveling 83-87 steps after activating the glitch in and landing the final step on the door of 's house, the player will now be in. Then the player should walk to either the Celadon City Pokémon Center, or the Celadon Condominiums building and immediately walk out and travel an additional 188-191 steps, landing the final step in the right-most entrance of the Celadon Department Store.

In international releases
The Dokokashira door glitch still exists in, but it's not available in early game, as select glitches were removed in international releases. However, triggering this glitch is still possible by with  or ZZAZZ glitch. Some of the effects from are still present, such as map tiles changing every 4 steps, or random Pokémon fainting even though nothing is poisoned. There also exist some effects which didn't happen in Pokémon Red, Green and Blue, like glitchy music and changing item quantities. In international releases, Dokokashira door glitch does not change the warp location.

Name origin
The English name of this glitch stems directly from the Japanese name. "Dokokashira" is a transliteration of the Japanese word "どこかしら", which translates to "somewhere" (or something more close to "somehow," except it specifies a place). The rest of the name is simply a translation of the Japanese name. The Japanese name is taken from the gadget "Dokodemo-Door" ("どこでもドア", literally "anywhere-door") from the long-running Japanese manga Doraemon, which is highly popular in Japan. The gadget is a door-shaped machine that takes people to an arbitrary distant place, by entering the destination and just opening it. This was related to the glitch's feature where it makes the undefined to warp to distant places after walking through the door into 's house, except that the destinations are seemingly random - hence getting "Somewhere-door."