Dokokashira door glitch

Select glitches in Japanese Pokémon Red, Green and Blue

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The doko kashira door glitch is one of the more notable examples of select bugs, which only exist within the Japanese Pokémon Red and Green. It is perhaps the most well known example in Japan and outside of Japan with the original Youtube video having over two million views. The glitch, amongst other select bugs were documented within the website pokemonbug with URL pokemonbug.oh.land.to and was later referenced by many other (especially Japanese) Pokémon glitch related websites. The phrase "doko kashira" is a transliteration of the Japanese word "どこかしら", literally meaning "where is it?", perhaps in reference to the glitch's arbitrary nature, where without careful planning it is difficult to predict the next location the player is going to arrive.

Please note that this glitch only exists in the Japanese versions of the game, or is otherwise a glitch
from a Pokémon game which was only released in Japan.

Bulbapedia also has an article about Dokokashira door glitch.

File:Dokokashira.png

Presuming that the player has recently started a New Game, in Pokémon Green. After the player switches the second item: Oak's Parcel with the first Pokémon the values of various RAM addresses will be 'switched'. For example, Professor Oak will be forced to appear outside of Pallet Town and importantly, the map identifier managed by certain warps in the area will start at a constant and deplete every four steps until reaching zero.

This select bug has been primarily exploited for the manipulation of the map identifier that another entrance, or exit will take the player to. It has been fairly popular for tool-assisted speedruns of Pokémon Red and Green even outside of Japan because of fast routes allowing the player to warp to the Hall of Fame, usually in under five minutes. However, doko kashira door glitch TAS submissions relating to the Generation I main-series Pokémon games have since been obsoleted by save corruption techniques.

As with all select bugs, the doko kashira door glitch is no longer exploitable in the special edition, Japanese Pokémon Blue because the updated engine of Pokémon Blue no longer keeps the select flag as set (1), if the player has recently pressed the select button on an item and closed the item pack. Additionally, the updated game engine of Japanese Pokémon Blue prevents the possibility of 'switching an item with a Pokémon'. Since the newer localizations of the first generation of main-handheld Pokémon games were based off the game engine of the original Japanese Pokémon Blue, the doko kashira door glitch and any other select bugs are not exploitable in European, NTSC or Korean localizations of the game.

Explanation

Main article:Select bugs

Requirements

A Japanese version of Pokémon Red, or Pokémon Green.
This glitch may not be successful in later areas of the game.
Two items in the player's bag, with Oak's Parcel as the second.
At least one Pokémon.

Triggering the exploit (Pokémon Green)

Open the item pack, preferably when in battle.
Press the select button on the second item (Oak's Parcel)
Exit the menu via B,B or return to the battle interface via B.
If not already in battle, enter a battle now without opening the menu again.
Open the party screen (from battle) and choose the first Pokémon to 'switch it with Oak's Parcel', it is now an 'Anedapami'.
Enter the FIGHT screen (this is important.
Either run away from battle, or defeat the enemy Pokémon (defeating the opponent allows the player to battle with 'Andepami' although the game will freeze if moves such as Growl are used by the opponent.

Related mechanics and route calculation

After triggering the glitch, the next warp location for entrances, where in which case the associated map number is affected by the doko kashira door glitch is set to a constant, depending on the map location that the player was when he or she exploited the glitch. This value decreases by 1 every 4 steps and changes the value of map number address D2DD to what was stored (which is representable by k-s/4 where 's' is a 'steps taken value', though 's' is not an internal mechanic) when the player is warped from such an entrance. The 'warp constant' "k", is refreshed by certain entrances which don't warp the player to the wrong location, where when entered or exited the amount of steps taken 's' is reset to 0.

If k-s/4 falls below 0, the warp location the player would be taken to remains at Pallet Town and does not loop back to value 255 if an additional four steps are taken.

Calculation

From the information above, the warp I.D is determined by Warp I.D= k-(steps/4), where "Warp I.D" is the decimal identifier of a desired map location, where k is the "warp constant" and where steps are the amount of steps taken by the player.

This can be re-arranged as Steps = 4k - (4 * warp I.D) to plan a route to a desired map location by adding values for k (the warp constant) and the warp I.D, as long as the result does not fall below zero.

List of locations by identifier

Please see here: [1]

List of entrances which refresh the 'step count' and 'warp constant'

This section is incomplete, please feel free to add any missing information about the subject. It is missing: {{{1}}}.

Associated map	Entrances
Pallet Town/Route 1	Start/finish of Route 1, player's house, Professor Oak's Lab
Celadon City	Pokémon Center, Celadon Condominiums, proceed from Route 16

List of warp constants