Pokémon data structure (Generation III)

Pokémon in the Pokémon Ruby and Sapphire, FireRed and LeafGreen, and Emerald Versions are all stored the same way in a 100-byte structure. All numbers are stored in little-endian order.


type offset
Personality value dword 0
OT ID dword 4
Nickname 10 bytes 8
Language byte 18
Egg Name byte 19
OT name 7 bytes 20
Markings byte 27
Checksum word 28
???? word 30
Data 48 bytes 32
Status condition dword 80
Level byte 84
Pokérus remaining byte 85
Current HP word 86
Total HP word 88
Attack word 90
Defense word 92
Speed word 94
Sp. Attack word 96
Sp. Defense word 98

Personality value

The personality value controls many things, including gender, Unown's letter, Spinda's dots, any Pokémon's Nature, and more.


The Original Trainer's ID number. This number is part of the XOR encryption key for the data section, and is also used in Shiny determination and the lottery. The least significant bytes of this number are the Trainer ID visible on the status screen. The most significant bits (top 16) are the Secret ID of the trainer that caught it.


The Pokémon's nickname, limited to 10 characters. The characters represented by each byte are determined by the proprietary character set.


The language of origin is language of the game the Pokémon originates from.

In Western languages, a Pokémon's language of origin determines which font to use to display its name and Original Trainer. This allows the names and Original Trainers of Pokémon from Japanese games to display correctly, including displaying Latin letters as fullwidth characters.

In Japanese, the language of origin is entirely ignored—names are always rendered using the Japanese character set. This causes all names to be truncated to five characters (even though they can be up to 10 characters in Western languages). In some cases, this causes characters to render as mojibake; for example, if the in-game trade Seel from Spanish Pokémon FireRed and LeafGreen (whose nickname is normally SEELÍN) is traded to a Japanese game, its nickname will be displayed as SEELコ.

The values that the languages correspond to are:

Index Language
1 Japanese
2 English
3 French
4 Italian
5 German
6 unused
7 Spanish

In the Generation III games, Eggs always have their language set to Japanese. This does not cause any issues as, upon hatching, the language of the Egg is set to the language of the game it hatched in.

Egg Name

This byte houses 3 flags:

  • Is Bad Egg (Bit 0): When this flag is set, the Pokémon will be treated as a Bad Egg. If a Pokémon's checksum is invalid, this flag is set, marking it as a Bad Egg and making it unusable.
  • Has Species (Bit 1): This flag is set whenever the Pokémon species index is non-zero, which should be the case for any Pokémon. It is used as a sanity check for empty spaces, and any Pokémon without this flag set cannot be bred and will disappear when group selected.
  • Use Egg Name (Bit 2): When this flag is set, the Pokémon will ignore their nickname and display the game's regional variant of "EGG". Only eggs should have this flag set. Note that this flag is independent from the egg flag in the subdata structure.
  • Bits 3-7: These bits are unused, and are just padding for the three flags. They should be set to 0.

OT name

The name of the Pokémon's Original Trainer. The characters represented by each byte are determined by the proprietary character set.


The markings seen in the storage Box. These markings serve only to aid in organizing large collections of Pokémon.

Bit Mark


The checksum for the 48-byte data section of this structure. It is computed by adding all of the unencrypted values of that section one word at a time. If the computed sum and the stored checksum do not match, the Pokémon is interpreted as a Bad Egg.


Unknown, possibly simply padding (not used and usually set to either 0 or -1, depending on the data type).


Certain data pertaining to the Pokémon that is stored in a special and encrypted format.

Status condition

The Pokémon's status condition is stored as follows:

Bit Status
0-2 SLP Sleep
3 PSN Poison
4 BRN Burn
5 FRZ Freeze
6 PAR Paralysis
7 PSN Bad Poison

The three sleep bits are used to indicate turns of sleep. So 1112 = 7 turns of sleep, 1012 = 5 turns, et cetera.


  This section is incomplete.
Please feel free to edit this section to add missing information and complete it.
Reason: What happens when this value ticks down to 0? What determines when it ticks down?
Main article: Pokérus

Not the same as the value found in the miscellaneous data substructure, which is a standard Pokérus byte. Instead, this value starts at 0xFF (and is in fact set to 0xFF initially even for Pokémon who haven't contracted Pokérus) and slowly ticks down. Cured Pokémon have this value set to 0.

Data location

  This section is incomplete.
Please feel free to edit this section to add missing information and complete it.
Reason: Are the addresses below only for US games? Also, is the mentioned "general region" of box data correct?

A Trainer's party starts at the following addresses in the GBA's RAM.

Game Address
Ruby 0x03004360
Emerald 0x02024190
FireRed 0x02024284
LeafGreen 0x020241E4

An opponent's party, or a wild Pokémon, starts at the following addresses.

Game Address
Ruby 0x030045C0
Emerald 0x02024744
FireRed 0x0202402C

The 600 bytes following these addresses describe a whole team of 6 Pokémon.

The full 100-byte structure for a Pokémon is only used to describe Pokémon being held in the player's party. When Pokémon are stored in the PC, their data is recorded using only the first 80 bytes of this structure, stopping after the data field. The last 20 bytes (excepting status condition, current HP, and Pokerus remaining byte) can all be recalculated from data in the data substructure when a Pokémon is withdrawn (level being derived from experience). This also explains why Pokémon suffering a status condition are "cured" when put in the PC.

This means there are also 33,600 bytes (80 bytes * 30 per Box * 14 Boxes) elsewhere in the GBA's RAM describing Pokémon in the PC. When the GBA's saved state (including memory contents) is unzipped into a 740,000+ byte file and viewed, the 14 Boxes of 420 Pokémon are stored in the general region of $038000 and $040000. In the US version of Pokémon Emerald, box data is between 0x02FE9888 and 0x02FF1BC8, non-inclusive. (Some emulators may address their RAM slightly differently.) The first 6 80-byte structures make up, from left to right, the first row of Pokémon in box 1. The next Pokémon gets placed on the next row. After 5 rows (30 80-byte structures), the next Pokémon is placed in box 2, and so on.

See also


Data structure in the Pokémon games
Generation I Pokémon speciesPokémonPoké MartCharacter encodingSave
Generation II Pokémon speciesPokémonTrainerCharacter encoding (Korean) • Save
Generation III Pokémon species (Pokémon evolutionPokédexType chart)
Pokémon (substructures) • MoveContestContest moveItem
Trainer TowerBattle FrontierCharacter encodingSave
Generation IV PokémonSaveCharacter encoding
Generation V-present Character encoding
TCG GB and GB2 Character encoding

  This data structure article is part of Project Games, a Bulbapedia project that aims to write comprehensive articles on the Pokémon games.