Save data structure in Generation II

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The save data structure for Generation II is stored in the cartridge's battery-backed RAM chip (SRAM), or as a ".sav" file from most emulators. The structure consists of 32 KB of data, though not every byte is used. Emulators may append additional data for the purposes of maintaining real-time clock operations.

Two regions of the save data have their integrity validated via checksums. These region contain all of the information that directly pertains to the player and his or her Pokémon. Additional information pertinent to the save file is also present in the other regions of the data.

Data types

Unless otherwise noted, integer values occupy the specified number of bytes, and are big-endian and either unsigned or two's complement.

Text data is stored in a proprietary encoding.

Item lists

Lists of items in the save data follow a particular format.

Lists have entries of 2 bytes each, and a capacity. The total size of the list data, in bytes, is Capacity * 2 + 2.

For example, the player's pocket inventory can hold 20 item entries, so the size of that list is 20 * 2 + 2 = 42 bytes.

Offset Size Contents
0x00 1 Count
0x01 2 * Capacity Item entries
... 1 Terminator

Count

The number of item entries actually being represented in the list. Note that count and capacity are not the same thing.

Entries

The exact data for each item entry in the list. For more information, see below.

Terminator

The byte following the last item entry, according to Count, must always be a terminator, which is byte value 0xFF.

This spare byte is present at the end of the list data for the event when the list is filled to capacity.

Entry format

The Entry record has the following format:

Offset Size Contents
0x00 1 Count
0x01 1 Index

Count

The amount of that particular item. Must be between 1 and 99, inclusive.

Index

The item's index.

Pokémon lists

Lists of Pokémon in the save data follow a particular format.

Lists have entries of varying sizes, and a capacity. The total size of the list data in bytes is Capacity * (Size + 23) + 2 in a save file from an English game, and Capacity * (Size + 13) + 2 in a save file from a Japanese game.

For example, the player's Pokémon team contains 6 entries and each entry is 48 bytes in size, so the size of that list is 6 * (48 + 23) + 2 = 428 bytes in an English save file, and 6 * (48 + 13) + 2 = 368 bytes in a Japanese one.

Offset Size Contents
0x0000 1 Count
0x0001 Capacity + 1 Species
... Capacity * Size Pokémon
... Capacity * 11 OT Names
... Capacity * 11 Names

Count

The number of Pokémon entries actually being represented in the list. Note that the count and the count and the capacity are not the same thing - a Pokémon list may have a capacity of, say, 30 Pokémon but only use a few of those slots. The count tells how many are actually used.

Species

A list of species indexes, one for each Pokémon in the list. This is used by the team menu as well as the PC management interface.

The byte following the last species entry, according to Count, must always be a terminator, which is the byte 0xFF. This means the species section is one byte longer than just the index numbers would make it.

If an entry in this field is set to 0xFD, then the corresponding Pokémon is still in its egg.

Pokémon

The exact data for each Pokémon entry in the list. For the format, please refer to: Pokémon data structure in Generation II

  • For team Pokémon, the entry size is the full 48 bytes as documented in that article.
  • For PC Pokémon, only the first 32 bytes are used, meaning everything after Level is not included. Instead, those values are regenerated upon withdrawing a Pokémon from the PC. This is the basis of the Box trick.

OT names

Text strings representing the names of the original Trainers for each Pokémon entry. Each name can contain up to 10 characters in a save file from an English game, and up to 5 characters in a save file from Japanese one. Following the 10 or 5 bytes, there is always one 0xFF byte, for a total of 11 or 6 bytes per name.

Names

Text strings representing the names for each Pokémon entry. Each name can contain up to 10 characters in a save file from an English game, and up to 5 characters in a save file from Japanese one. Following the 10 or 5 bytes, there is always one 0xFF byte, for a total of 11 or 6 bytes per name.

A name is considered a "nickname" if it does not perfectly match the default name for a Pokémon. The default name follows these rules:

  • The first however many characters must match the species name exactly. This is typically all-uppercase.
  • The remainder of the string must be all terminator characters, aka 0x50.

Therefore, if a Pokémon with a 9- or 10-letter species name, such as Charmander, is given a nickname that matches the species name, the nickname will not be retained should that Pokémon evolve.

File structure

Known data within the save file can be found at the following offsets within the data, such that offset 0 is the first byte of an emulator ".sav" file.

Although all data appears twice in the save file, only the primary copy is documented below. For more information, see the Checksums section.

English and Japanese save files are quite a bit different, mostly due to Japanese Generation II games having 9 boxes in the PC of 30 Pokémon each, while the English games have 14 boxes of 20 each. The save format also differs between game versions, as Crystal has more features than Gold and Silver.

English Japanese Contents
Offset Size Offset Size
GS C GS C
0x2000 0x2000 8 0x2000 0x2000 8 Options
0x2009 0x2009 2 Player Trainer ID
0x200B 0x200B 11 Player name
0x2013 0x2013 11 Unused (Player's mom name)
0x2021 0x2021 11 Rival name
0x201C 0x201C 11 Unused (Red's name)
0x2013 0x2013 11 Unused (Blue's name)
0x2037 0x2037 1 Daylight savings
0x2053 0x2054 4 Time played
0x206B 0x206A 1 Player palette
0x23DB 0x23DC 3 Money
0xD57C 0x23E5 1 Johto Badges
0x23E6 0x23E7 57 TM pocket
0x241F 0x2420 42 Item pocket item list
0x2449 0x244A 54 Key item pocket item list
0x2464 0x2465 26 Ball pocket item list
0x247E 0x247F 102 PC item list
0x2724 0x2700 1 Current PC Box number
0x2727 0x2703 126 0x2708 0x26E5 81 PC Box names
0x288A 0x2865 428 0x283E 0x281A 368 Team Pokémon list
0x2A4C 0x2A27 32 Pokédex owned
0x2A6C 0x2A47 32 Pokédex seen
0x2D6C 0x2D10 1102 0x2D10 0x2D10 1352 Current Box Pokémon list
N/A 0x3E3D 1 N/A 1 Player gender
0x4000 0x4000 1102 0x4000 0x4000 1352 PC Box 1 Pokémon list
0x4450 0x4450 1102 0x454A 0x454A 1352 PC Box 2 Pokémon list
0x48A0 0x48A0 1102 0x4A94 0x4A94 1352 PC Box 3 Pokémon list
0x4CF0 0x4CF0 1102 0x4FDE 0x4FDE 1352 PC Box 4 Pokémon list
0x5140 0x5140 1102 0x5528 0x5528 1352 PC Box 5 Pokémon list
0x5590 0x5590 1102 0x5A72 0x5A72 1352 PC Box 6 Pokémon list
0x59E0 0x59E0 1102 0x6000 0x6000 1352 PC Box 7 Pokémon list
0x6000 0x6000 1102 0x654A 0x654A 1352 PC Box 8 Pokémon list
0x6450 0x6450 1102 0x6A94 0x6A94 1352 PC Box 9 Pokémon list
0x68A0 0x68A0 1102 N/A PC Box 10 Pokémon list
0x6CF0 0x6CF0 1102 N/A PC Box 11 Pokémon list
0x7140 0x7140 1102 N/A PC Box 12 Pokémon list
0x7590 0x7590 1102 N/A PC Box 13 Pokémon list
0x79E0 0x79E0 1102 N/A PC Box 14 Pokémon list
0x2D69 0x2D0D 2 0x2D0D Checksum 1
0x7E6D 0x1F0D 2 0x7F0D Checksum 2

Player name

Represents text strings that can be from 1 to 7 characters in length, although the save structure allocates 11 bytes for the name.

The first 8 bytes contain the name with any leftover equal to 0x50.

Since the name can be 7 bytes at most, the eighth byte will always be 0x50.

The remaining 3 bytes are all 0x00.

Rival name

Represents text strings that can be from 1 to 7 characters in length, although the save structure allocates 11 bytes for the name.

The first 8 bytes contain the name with any leftover equal to 0x50.

Since the name can be 7 bytes at most, the eighth byte will always be 0x50.

The remaining 9th, 10th, and 11th bytes are equal to 0x86, 0x91, 0x84 respectively.

Daylight savings

Specifies whether daylight savings time (DST) is in effect.

The highest bit of this field is set to indicate DST is in effect.

The lower 7 bits of this field have unknown significance.

Time played

Specifies how much time has elapsed during gameplay.

This value is actually 4 1-byte values representing, in this order: the hours, minutes, seconds and "frames" that have elapsed. A frame is 1/60th of a second.

This timer is not halted when the game is paused, and also counts up on the main menu before selecting to continue a saved game.

Player palette

Specifies the colors of the player character.

From a technical standpoint, the lowest 3 bits of this field are transferred to OAM to select the colors when drawing the player character. This means that there are a total of 8 possible palettes:

  • Red, 0x00
  • Blue, 0x01
  • Green, 0x02
  • Brown, 0x03
  • Orange, 0x04
  • Gray, 0x05
  • Dark Green, 0x06
  • Dark Red, 0x07

From a practical standpoint, this value is set by the game depending on whether the player character is a boy or a girl:

  • For boy characters, this is set to 0x00 (red)
  • For girl characters, this is set to 0x01 (blue)

Despite only being able to make boy characters in Gold and Silver, this field is still present and functional.

Johto Badges

The eight badges are stored on eight bits, one bit for each badge; '1' means the badge is acquired, '0' otherwise.

From MSB to LSB, badges are in this order: Zephyr, Insect, Plain, Fog, Storm, Mineral, Galcier, Rising.

TM pocket

The items that the player has in his or her TM Pocket inventory.

Offset Size Contents
0x00 50 TMs list
0x32 7 HMs list

TMs list

Each byte specifies the quantity of the corresponding TM that the player is holding. Should be 0 to 99.

Indexes match item numbers, meaning 0 corresponds with TM01 and 49 corresponds with TM50.

HMs list

Each byte specifies the quantity of the corresponding HM that the player is holding. Should be 0 to 1.

Indexes match item numbers, meaning 0 corresponds with HM01 and 6 corresponds with HM07.

Item pocket item list

The items that the player has in his or her item pocket inventory.

Stored as an Item list with a capacity of 20.

Key item pocket item list

The items that the player has in his or her Key Item Pocket inventory.

Stored as an Item list with a capacity of 26.

Ball pocket item list

The items that the player has in his or her Ball Pocket inventory.

Stored as an Item list with a capacity of 12.

PC item list

The items that the player has stored in the PC.

Stored as an Item list with a capacity of 50.

Current PC Box

Indicates which PC box is currently selected, minus 1. That is to say, box 1 is represented as 0, and box 14 is represented as 13.

The lowest 4 bits of this value are the box index.

PC Box names

The 9 (Japanese game) or 14 (English game) box names. Each name is a string between 1 and 8 characters plus a terminator byte, for a total of 9 bytes each.

Team Pokémon list

The Pokémon that the player has in his or her team.

Stored as a Pokemon list with a capacity of 6 and an entry size of 48 bytes.

Pokédex owned, Pokédex seen

Represents the specific Pokédex entries that have been either seen or owned during gameplay.

Pokémon are indexed by their usual Pokédex order, meaning the order is the same as in the National Pokédex. However, indexes begin counting at 0, rather than 1.

1 bit is used to represent whether a given Pokémon has been seen/owned. Bits are ordered within bytes from lowest to highest, starting with the first byte. Therefore, the exact bit can be extracted from the list using the following formula:

Bit = ( Data[ RoundDown(PokeNum / 8) ] / 2 ^ (PokeNum Mod 8) ) AND 1

Or in C-style code (shift occurs before other bitwise operations):

Bit = Data[PokeNum >> 3] >> (PokeNum & 7) & 1;

Example

Let us say that we want to know whether #120 Staryu has been seen/owned:

  • PokeNum becomes 119, since it is 0-based.
  • The byte of the list in which bit 119 is located is = 119 / 8 = 14
  • The bit within that byte is = 119 Mod 8 = 7
  • Dividing the byte value by 2 ^ Bit, or shifting right by Bit, moves the bit to the least-significant position
  • Performing a bitwise AND with 1 will remove all but the least-significant bit

PC Box Pokémon lists

The Pokémon that the player has stored in PC boxes.

Stored as Pokemon lists with a capacity of 20 Pokémon in English save files and 30 in Japanese ones, and an entry size of 32 bytes. After every list is the two bytes FF00.

Normally, Pokémon are deposited and withdrawn from the Current Box list, which is within the checksum-validated region of the save data. When switching boxes, the data from the Current Box is copied to the corresponding PC Box data, then the data from the switched-to PC Box is transferred into the Current Box data.

Player gender

Specifies the gender of the player character:

  • For boy characters, this is set to 0x00
  • For girl characters, this is set to 0x01

This field is not within the checksum-validated region.

Checksums

Used to validate the integrity of saved data.

Player data in Generation II is stored in the save file twice. The primary copy is located at 0x2009, and a secondary copy is stored elsewhere in the file. Checksums are performed on both copies and stored in the data.

  • If only one checksum is correct, then the information from that copy of the data will be used.
  • If both values are incorrect, the player will be forced to start a new game.

The checksums are simply the 16-bit sum of all byte values of the corresponding byte regions. Checksums are stored as little-endian.

Gold and Silver

The secondary data copy in Gold and Silver is not contiguous like the primary copy is. Instead, it is split across 5 sections and stored at different locations in the save file. The following table shows which sections of the primary copy are relocated for the secondary copy:


Primary Secondary
From To From To
0x2009 0x222E 0x15C7 0x17EC
0x222F 0x23D8 0x3D96 0x3F3F
0x23D9 0x2855 0x0C6B 0x10E7
0x2856 0x2889 0x7E39 0x7E6C
0x288A 0x2D68 0x10E8 0x15C6

Calculating the checksums, therefore, can be done as follows:

  • Sum the bytes from 0x2009 to 0x2D68 and store the result at 0x2D69
  • Sum the bytes from 0x0C6B to 0x17EC, 0x3D96 to 0x3F3F and 0x7E39 to 7E6C, and store the result at 0x7E6D

Crystal

The secondary data copy in Crystal is a byte-for-byte match of the primary copy. The following table shows which regions of the save file are occupied by each copy:

Primary Secondary
From To From To
0x2009 0x2B82 0x1209 0x1D82

Calculating the checksums, therefore, can be done as follows:

  • Sum the bytes from 0x2009 to 0x2B82 and store the result at 0x2D0D
  • Sum the bytes from 0x1209 to 0x1D82 and store the result at 0x1F0D

For Japanese games, the secondary partition is from 0x7209 to 0x7D3A the checksums can be calculated as follows:

  • Sum the bytes from 0x2009 to 0x2B3A and store the result at 0x2D0D
  • Sum the bytes from 0x7209 to 0x7D3A and store the result at 0x7F0D


Data structure in the Pokémon games
Generation I Pokémon data structurePokémon base stats data structureSave data structureCharacter encoding
Generation II Pokémon data structurePokémon base stats data structureTrainer data structureSave data structureCharacter encoding
Generation III Pokémon data structurePokémon data substructuresPokémon base stats data structureMove data structure
Contest data structureContest move data structureItem data structurePokédex data structureBattle Frontier data structures
Trainer Tower data structuresPokémon evolution data structureType Chart data structureSave data structureCharacter encoding
Generation IV Pokémon data structureSave data structure

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