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In the early Generation I and II games, many glitches contained Japanese Katakana and Hiragana text; most notably the ゥ. The English games were not supposed to contain any Japanese characters at all, however, some characters were left behind within the coding.
Below are the only characters known to be programmed into the games.
Gen I
Blue's Main screen tiles at address 0x8800, Notice ァ, ゥ, and ェ below the Pokémon logo.
Yellow's overworld tiles at address 0x8800, Notice ぁ, ぇ, and ぉ on the last line.
Yellow's in-battle tiles at address 0x8000, Notice ァ, ゥ, and ェ on the second-to-last line.
Yellow's main screen tiles at address 0x8800, Notice ァ, ゥ, and ェ on the middle line and ぁ, ぇ, and ぉ on the last line.
R/B
Maintiles
| Address
|
Character
|
| 8E90
|
ァ (a)
|
| 8EA0
|
ゥ (u)
|
| 8EB0
|
ェ (e)
|
Overworld tiles
| Address
|
Character
|
| 9760
|
ぁ (a)
|
| 9770
|
ぇ (e)
|
| 9780
|
ぉ (o)
|
Battletiles
| Address
|
Character
|
| 8E90
|
ァ (a)
|
| 8EA0
|
ゥ (u)
|
| 8EB0
|
ェ (e)
|
Yellow
Maintiles
| Address
|
Character
|
| 8E90
|
ァ (a)
|
| 8EA0
|
ゥ (u)
|
| 8EB0
|
ェ (e)
|
| 9760
|
ぁ (a)
|
| 9770
|
ぇ (e)
|
| 9780
|
ぉ (o)
|
Overworld tiles
| Address
|
Character
|
| 9760
|
ぁ (a)
|
| 9770
|
ぇ (e)
|
| 9780
|
ぉ (o)
|
Battletiles
| Address
|
Character
|
| 9760
|
ぁ (a)
|
| 9770
|
ぇ (e)
|
| 9780
|
ぉ (o)
|
Gen II
G/S
Gold's Main screen tiles at address 0x8800, Notice ぁ, ぇ, and ぉ on the last line.
Maintiles
| Address
|
Character
|
| 9760
|
ぁ (a)
|
| 9770
|
ぇ (e)
|
| 9780
|
ぉ (o)
|
Overworld tiles
| Address
|
Character
|
| 9760
|
ぁ (a)
|
| 9770
|
ぇ (e)
|
| 9780
|
ぉ (o)
|
Gold's in-battle screen tiles at address 0x8800, Notice ど on the bottom left.
Battletiles
| Address
|
Character
|
| 9700
|
ど (Do)
|
Crystal
Crystal's Main screen tiles at address 0x8800, Notice ぁ, ぇ, and ぉ on the last line.
Maintiles
| Address
|
Character
|
| 9760
|
ぁ (a)
|
| 9770
|
ぇ (e)
|
| 9780
|
ぉ (o)
|
Overworld tiles
| Address
|
Character
|
| 9760
|
ぁ (a)
|
| 9770
|
ぇ (e)
|
| 9780
|
ぉ (o)
|
Battletiles
| Address
|
Character
|
| 9700
|
ど (Do)
|