Chunk format – Minecraft Wiki (original) (raw)

This article needs to be updated.

Please update this page to reflect recent updates or newly available information.
Reason: missing information about 1.18 formats, this page is W.I.P. and sections that are updated for 1.18 mention it.

For the storage format of entities, see Entity format.

Chunks store the terrain and entities within a 16×384×16 area in The Overworld, and 16×256×16 in The Nether and The End by default. They also store precomputed lighting, heightmap data for Minecraft's performance, and other meta information.

NBT structure[edit | edit source]

Chunks are stored as tags in regional Minecraft Anvil files, which are named in the form r.x.z.mca. They are stored in NBT format, with the following structure (updated for 1.18):

• The root tag.
  • DataVersion: Version of the chunk NBT structure.
  • xPos: X position of the chunk (in absolute chunks from world x, z origin, not relative to the region).
  • zPos: Z position of the chunk (in absolute chunks from world x, z origin, not relative to the region).
  • yPos: Lowest Y section position in the chunk (e.g. -4 in 1.18).
  • Status: Defines the world generation status of this chunk. It is always one of the following: minecraft:empty, minecraft:structure_starts, minecraft:structure_references, minecraft:biomes, minecraft:noise, minecraft:surface, minecraft:carvers, minecraft:features, minecraft:light, minecraft:spawn, or minecraft:full. All status except minecraft:full are used for chunks called proto-chunks, in other words, for chunks with incomplete generation.
  • LastUpdate: Tick when the chunk was last saved.
  • sections: List of Compounds, each tag is a section (also known as sub-chunk). All sections in the world's height are present in this list, even those who are empty (filled with air).
    * An individual section.
    * Y: The Y position of this section. (Can also be an INT in 1.18+)
    * block_states
    * palette: Set of different block states used in this particular section.
    * A block
    * Name: Block resource location
    * Properties: List of block state properties, with name being the name of the block state property
    * Name: The block state's name and its value.
    * data: A packed array of 4096 indices pointing to the palette, stored in an array of 64-bit integers ( Longs).
    * If only one block state is present in the palette, this field is not required and the block fills the whole section.
    * All indices are the same length. This length is set to the minimum amount of bits required to represent the largest index in the palette, and then set to a minimum size of 4 bits. Since 1.16, the indices are not packed across multiple elements of the array, meaning that if there is no more space in a given 64-bit integer for the whole next index, it starts instead at the first (lowest) bit of the next 64-bit integer. Different sections of a chunk can have different lengths for the indices.
    * biomes
    * palette: Set of different biomes used in this particular section.
    * Name: Biome resource location
    * data: A packed array of 64 indices pointing to the palette, stored in an array of 64-bit integers ( Longs).
    * If only one biome is present in the palette, this field is not required and the biome fills the whole section.
    * All indices are the same length: the minimum amount of bits required to represent the largest index in the palette. These indices do not have a minimum size. Different chunks can have different lengths for the indices.
    * BlockLight: 2048 Bytes stores the amount of block-emitted light in each block. Makes load times faster compared to recomputing at load time. Omitted if no light reaches this section of the chunk. Light level is stored as 4 bits per block, 2 blocks sharing a byte: starting at 0, even blocks take the first nibble, and odd blocks the second one.
    * SkyLight: 2048 Bytes stores the maximum sky light that reaches each block, regardless of current time. If the sky light data for a section is omitted you should look at the light data of the section directly above it. Take the 16x16 layer at the bottom of that section and repeat that light data 16 times to recompute the data for the omitted section. If there is no section above the current one, you are at the top section of the chunk. The light data for this top section should be set as completely bright (0xFF for each block). The format of how these levels is stored is the same as for BlockLight.
  • block_entities: Each Compound in this list defines a block entity in the chunk.
    * See Block Entity Format below.
    * If this list is empty, it becomes a list of End tags.
  • CarvingMasks: Only for proto-chunks (not confirmed for 1.18 format).
    * AIR: A series of bits indicating whether a cave has been dug at a specific position, stored in a byte array.
    * LIQUID: A series of bits indicating whether an underwater cave has been dug at a specific position, stored in a byte array.
  • Heightmaps: Several different heightmaps corresponding to 256 values compacted at 9 bits per value (lowest being 0, highest being 384, both values inclusive). The 9-bit values are stored in an array of 37 Longs, each containing 7 values ( A Long = 64 bits, 7×9 = 63; the last bit is unused). In versions prior to 1.16 the heightmaps were stored in 36 Long values, where the bits were arranged in an uninterrupted "stream" across all values, resulting in all 2304 bits being used. The 9-bit values are unsigned, and indicate the amount of blocks above the bottom of the world. This means that converting a world to 1.18 adds 64 to every value.
    * MOTION_BLOCKING
    * MOTION_BLOCKING_NO_LEAVES
    * OCEAN_FLOOR
    * OCEAN_FLOOR_WG
    * WORLD_SURFACE
    * WORLD_SURFACE_WG
  • Lights: A List of 16 lists that store positions of light sources per chunk section as shorts, only for proto-chunks (not confirmed for 1.18 format).
  • Entities: A list of entities in the proto-chunks, used when generating. As of 1.17, this list is not present for fully generated chunks and entities are moved to a separated region files once the chunk is generated, see Entity format for more details (not confirmed for 1.18 format).
    * : An entity.
  • fluid_ticks: A list of Compounds
    * Each Compound in this list is an "active" liquid in this chunk waiting to be updated. See Tile Tick Format below.
  • block_ticks: A list of Compounds
    * Each Compound in this list is an "active" block in this chunk waiting to be updated. These are used to save the state of redstone machines or falling sand, and other activity. See Tile Tick Format below.
  • InhabitedTime: The cumulative number of ticks players have been in this chunk. Note that this value increases faster when more players are in the chunk. Used for Regional Difficulty.
  • blending_data: This appears to be biome blending data, although more testing is needed to confirm. ​[_more information needed_]
    * min_section: ​[_more information needed_]
    * max_section: ​[_more information needed_]
  • PostProcessing: A List of 24 Lists that store the positions of blocks that need to receive an update when a proto-chunk turns into a full chunk, packed in Shorts. Each list corresponds to specific section in the height of the chunk.
    * See ToBeTicked format below for a description of the coordinate packing format. A common use case for this to is make liquids flow after generating a source block, such as springs in caves.
  • structures: Structure data in this chunk.
    * References: Coordinates of chunks that contain Starts.
    * Structure Name: Each 64-bit number of this array represents a chunk coordinate (i.e. block coordinate / 16), with its X packed into the low (least significant) 32 bits and Z packed into the high (most significant) 32 bits.
    * starts: Structures that are yet to be generated, stored by general type. Some parts of the structures may have already been generated. Completely generated structures are removed by setting their id to "INVALID" and removing all other tags.
    * Structure Name: Only the structures that can spawn in this dimension are stored, for example, EndCity is stored only in the end chunks.
    * BB: Bounding box of the entire structure (remaining Children). Value is 6 ints: the minimum X, Y, and Z coordinates followed by the maximum X, Y, and Z coordinates. Absent if id is INVALID.
    * biome: The biome id this structure is in. Absent if id is INVALID.
    * Children: List of structure pieces making up this structure, that were not generated yet. Absent if id is INVALID.
    * Structure piece data. ​[_more information needed_]
    * BB: Bounding box of the structure piece. (Does not include the part of a village roof that can overhang the road.) Value is 6 ints: the minimum X, Y, and Z coordinates followed by the maximum X, Y, and Z coordinates.
    * BiomeType: The ocean temperature this ocean ruins is in. Valid values are WARM and COLD.
    * C: (Village "ViSmH") Hut roof type.[_verify_]
    * CA: (Village "ViF" and "ViDF") Crop in the farm plot.[_verify_]
    * Name: Block resource location
    * Properties: List of block state properties, with [name] being the name of the block state property
    * Name: The block state name and its value.
    * CB: (Village "ViF" and "ViDF")
    * separate object with the same format as CA
    * CC: (Village "ViDF")
    * separate object with the same format as CA
    * CD: (Village "ViDF")
    * separate object with the same format as CA
    * Chest: 1 or 0 (true/false) - (Fortress "NeSCLT" and "NeSCRT") Whether this fortress piece should contain a chest but hasn't had one generated yet. (Stronghold "SHCC") Whether this chest in this stronghold piece was placed. (Village "ViS") Whether the blacksmith chest has been generated.
    * D: (Mineshaft "MSCrossing") Indicates the "incoming" direction for the crossing.
    * Depth: (Temples and huts) Depth of the structure (X/Z).
    * Entrances: (Mineshaft "MSRoom") List of exits from the room.
    * : Bounding box of the exit.
    * EntryDoor: (Stronghold) The type of door at the entry to this piece.
    * GD: Appears to be some sort of measure of how far this piece is from the start.
    * hasPlacedChest0: 1 or 0 (true/false) - (Desert temple) Whether 1st chest was placed.
    * hasPlacedChest1: 1 or 0 (true/false) - (Desert temple) Whether 2nd chest was placed.
    * hasPlacedChest2: 1 or 0 (true/false) - (Desert temple) Whether 3rd chest was placed.
    * hasPlacedChest3: 1 or 0 (true/false) - (Desert temple) Whether 4th chest was placed.
    * Height: (Temples and huts) Height of the structure (Y).
    * HPos: (Temples, huts and villages) Y level the structure was moved to in order to place it on the surface, or -1 if it hasn't been moved yet.[_verify_]
    * hps: 1 or 0 (true/false) - (Mineshaft "MSCorridor") Whether the corridor has a cave spider monster spawner.
    * hr: 1 or 0 (true/false) - (Mineshaft "MSCorridor") Whether the corridor has rails.
    * id: Identifier for the structure piece. Typically a heavily abbreviated code rather than something human-readable. ​[_more information needed_]
    * integrity: The integrity of this structure (only used by ocean ruins).
    * isLarge: 1 or 0 (true/false) - If this ocean ruin is big.
    * junctions: (Village) List of junction points. ​[_more information needed_][_verify_]
    * : The junctions coordinates:
    * source_x: X.
    * source_ground_y: Y.
    * source_z: Z.
    * delta_y: Change Y. ​[_more information needed_]
    * dest_proj: One of terrain_matching or rigid.
    * Left: 1 or 0 (true/false) - (Stronghold "SHS") Whether the corridor has an opening on the left.
    * leftHigh: 1 or 0 (true/false) - (Stronghold "SH5C") Whether the 5-way crossing has an exit on the upper level on the side with the upward staircase.
    * leftLow: 1 or 0 (true/false) - (Stronghold "SH5C") Whether the 5-way crossing has an exit on the lower level on the side with the upward staircase.
    * Length: (Village "ViSR") Length of the road piece.[_verify_]
    * Mob: 1 or 0 (true/false) - (Fortress "NeMT") Whether this fortress piece should contain a blaze monster spawner but hasn't had one generated yet. (Stronghold "SHPR") Whether the silverfish monster spawner has been placed in this piece.
    * Num: (Mineshaft "MSCorridor") Corridor length.
    * O: Likely orientation of the structure piece.
    * placedHiddenChest: 1 or 0 (true/false) - (Jungle temple) Whether the hidden chest was placed.
    * placedMainChest: 1 or 0 (true/false) - (Jungle temple) Whether the main chest was placed.
    * placedTrap1: 1 or 0 (true/false) - (Jungle temple) Whether the hallway arrow trap dispenser was placed.
    * placedTrap2: 1 or 0 (true/false) - (Jungle temple) Whether the chest arrow trap dispenser was placed.
    * PosX: The X coordinate origin of this village part.[_verify_]
    * PosY: The Y coordinate origin of this village part.[_verify_]
    * PosZ: The Z coordinate origin of this village part.[_verify_]
    * Right: 1 or 0 (true/false) - (Stronghold "SHS") Whether the corridor has an opening on the right.
    * rightHigh: 1 or 0 (true/false) - (Stronghold "SH5C") Whether the 5-way crossing has an exit on the upper level on the side with the downward staircase.
    * rightLow: 1 or 0 (true/false) - (Stronghold "SH5C") Whether the 5-way crossing has an exit on the lower level on the side with the downward staircase.
    * Rot: Rotation of ocean ruins and shipwrecks. Valid values are COUNTERCLOCKWISE_90, NONE, CLOCKWISE_90, and CLOCKWISE_180.
    * sc: 1 or 0 (true/false) - (Mineshaft "MSCorridor") Whether the corridor has cobwebs.
    * Seed: (Fortress "NeBEF") Random seed for the broken-bridge fortress piece.
    * Source: 1 or 0 (true/false) - (Stronghold "SHSD") Whether the spiral staircase is the source of the Stronghold or was randomly generated.
    * Steps: (Stronghold "SHFC") Length of the corridor
    * T: (Village "ViSmH") Table: 0 is no table, 1 and 2 place it on either side of the hut.[_verify_]
    * Tall: 1 or 0 (true/false) - (Stronghold "SHLi") Whether the library has an upper level.
    * Template: The template of the ocean ruin or shipwreck that was used.
    * Terrace: 1 or 0 (true/false) - (Village "ViSH") Whether the house has a ladder to the roof and fencing.[_verify_]
    * tf: 1 or 0 (true/false) - (Mineshaft "MSCrossing") Whether the crossing is two floors tall.
    * TPX: The X coordinate origin of this ocean ruin or shipwreck.
    * TPY: The Y coordinate origin of this ocean ruin or shipwreck.
    * TPZ: The Z coordinate origin of this ocean ruin or shipwreck.
    * Type: (Village) Village type: 0=plains, 1=desert, 2=savanna, 3=taiga.[_verify_]
    * Type: (Stronghold "SHRC") Indicates whether the room contains a pillar with torches, a fountain, an upper level with a chest, or is just empty room.
    * VCount: (Village) Count of villagers spawned along with this piece.[_verify_]
    * Width: (Temples and huts) Width of the structure (X/Z).
    * Witch: 1 or 0 (true/false) - (Witch hut) Whether the initial witch has been spawned for the hut.
    * Zombie: 1 or 0 (true/false) - (Village) Whether this village generated as a zombie village.[_verify_]
    * ChunkX: Chunk X coordinate of the start of the structure. Absent if id is INVALID.
    * ChunkZ: Chunk Z coordinate of the start of the structure. Absent if id is INVALID.
    * id: If there's no structure of this kind in this chunk, this value is "INVALID", else it's the structure name.
    * Processed: (Monument only) List of chunks that have had their piece of the structure created. Absent if id is INVALID.
    * : A chunk.
    * X: The chunk's X position (chunk coordinates, not block coordinates).
    * Z: The chunk's Z position.
    * Valid: 1 or 0 (true/false) - (Village only) Whether the village generated at least 3 non-roads. Absent if id is INVALID.

Block format[edit | edit source]

In the Anvil format, block positions are ordered YZX for compression purposes.

The coordinate system is as follows:

• X increases East, decreases West
• Y increases upward, decreases downward
• Z increases South, decreases North

This means indices are ordered like in a book, with its top to the North, read from beneath and with words written backward: each letter is a different X-index, each line a Z-index, and each page a Y-index. In case of a flat 2D array, the Y-index is omitted, and the array reads like a single page.

Each section is a 16×16×16-block area, with up to 16 sections in a chunk : from 0 at the bottom, to 15 on top. Empty sections are not saved. Each section has a "Y" byte for its Y-index (0 to 15), a "Palette" list linking IDs to block states, and a "BlockStates" long array storing the IDs per block location, compressed by fitting multiple IDs inside each entry (see NBT_structure above for details on the compression). There might be an additional section at the top and or bottom of the world used to store light, so that light travels properly over and under the world limits.

The pseudo-code below shows how to access individual block information from a single section.

byte Nibble4(byte[] arr, int index){ return index%2 == 0 ? arr[index/2]&0x0F : (arr[index/2]>>4)&0x0F; } int BlockPos = y1616 + z*16 + x; compound Block = Palette[change_array_element_size(BlockStates,Log2(length(Palette)))[BlockPos]]; string BlockName = Block.Name; compound BlockState = Block.Properties; byte Blocklight = Nibble4(BlockLight, BlockPos); byte Skylight = Nibble4(SkyLight, BlockPos);

Block entity format[edit | edit source]

A block entity (not related to entity) is used by Minecraft to store information about a block that can't be stored in the block's block states. Block entities were called "tile entities" until the 1.18 snapshots and that term is still used in some command usage.

banners

• Block entity data
  • CustomName: Optional. The name of this banner in JSON text component, which is used for showing the banner on a map.
  • patterns: List of all patterns applied to the banner.
    * : An individual pattern.
    * color: Color of the section.
    * pattern: One Banner pattern (an ID, or a new Banner pattern definition) — The banner pattern the color is applied to.

Pattern color

Pattern

barrel

• Block entity data
  • CustomName: Optional. The name of this container in JSON text component, which appears in its GUI where the default name ordinarily appears.
  • Items: List of items in the container.
    * : An item, including the slot tag. Barrel slots are numbered 0-26, 0 starts in the top left corner.
  • Lock: Optional. When not blank, prevents the container from being opened unless the opener is holding an item whose name matches this string.
  • LootTable: Optional. Name of the loot table to use. If this is used in a chest-like container, the loot table generates its content when it is opened. Generating the items in the container removes both loot table tags ( LootTable and LootTableSeed).
  • LootTableSeed: Optional. Seed for generating the loot table. The default value works similarly to the seeds for worlds, where value of 0 or an omitted value causes the game to use a random seed.

beacon

• Block entity data
  • CustomName: Optional. The name of this beacon in JSON text component, which appears when attempting to open it, while it is locked.
  • Lock: Optional. When not blank, prevents the container from being opened unless the opener is holding an item whose name matches this string.
  • primary_effect: Optional. The primary effect selected, see Potion effects for resource locations. Cannot be set to an effect that beacons do not normally use. Although Regeneration cannot normally be chosen as the primary effect, setting this value to minecraft:regeneration works and even allows Regeneration II to be chosen as the secondary via the normal beacon GUI.
  • secondary_effect: Optional. The secondary effect selected, see Potion effects for resource locations. Cannot be set to an effect that beacons do not normally use. When set without a primary effect, does nothing. When set to the same as the primary, the effect is given at level 2 (the normally available behavior for 5 effects). When set to a different value than the primary (normally only Regeneration), gives the effect at level 1.

bed

• Block entity data

beehive

• Block entity data
  • bees: Entities currently in the hive.
    * An entity in the hive.
    * entity_data: The NBT data of the entity in the hive.
    * See entity format.
    * min_ticks_in_hive: The minimum amount of time in ticks for this entity to stay in the hive.
    * ticks_in_hive: The amount of ticks the entity has stayed in the hive.
  • flower_pos: Stores the flower block location, as 3 integers, so other bees can go to it.

bell

• Block entity data

blast_furnace

• Block entity data
  • lit_time_remaining: Number of ticks left before the current fuel runs out.
  • cooking_time_spent: Number of ticks the item has been smelting for. The item finishes smelting when this value reaches 200 (10 seconds). Is reset to 0 if lit_time_remaining reaches 0.
  • cooking_total_time: Number of ticks it takes for the item to be smelted.
  • lit_total_time: Represent the total time the furnace should be lit.
  • Items: List of items in this container.
    * : An item in the blast furnace, including the slot tag:
    Slot 0: The item(s) being smelted.
    Slot 1: The item(s) to use as the next fuel source.
    Slot 2: The item(s) in the result slot.
  • RecipesUsed: Recipes that have been used since the last time a recipe result item was manually removed from the GUI. Used to calculate experience given to the player when taking out the resulting item.
    * recipe ID: How many times this specific recipe has been used. The recipe ID is the identifier of the smelting recipe, as a resource location, as used in the /[recipe](/w/Commands/recipe "Commands/recipe") command.

brewing_stand

• Block entity data
  • BrewTime: The number of ticks the potions have to brew.
  • CustomName: Optional. The name of this container in JSON text component, which appears in its GUI where the default name ordinarily appears.
  • Fuel: Remaining fuel for the brewing stand. 20 when full, and counts down by 1 each time a potion is brewed.
  • Items: List of items in this container.
    * : An item in the brewing stand, including the slot tag:
    Slot 0: Left potion slot.
    Slot 1: Middle potion slot.
    Slot 2: Right potion slot.
    Slot 3: Where the potion ingredient goes.
    Slot 4: Fuel (Blaze Powder).
  • Lock: Optional. When not blank, prevents the container from being opened unless the opener is holding an item whose name matches this string.

calibrated_sculk_sensor

• : Block entity data.
  • last_vibration_frequency: The frequency of the last vibration.
  • listener: The vibration event listener for this sculk shrieker, sculk sensor, or calibrated sculk sensor.
    * event: Exists only if there is an incoming vibration.
    * distance: The distance between this vibration's source and the block.
    * game_event: The resource location of the vibration event that caused the current incoming vibration.
    * pos: The coordinates of the source of this vibration.
    * : X coordinate.
    * : Y coordinate.
    * : Z coordinate.
    * projectile_owner: If the vibration was caused by a projectile, this is the UUID of the entity that launched the projectile. Does not exist if vibration was not caused by a projectile.
    * source: The UUID of the entity that caused the vibration. Does not exist if vibration was not caused by an entity.
    * event_delay: How many ticks remain until triggered by the vibration. Set to 0 if there is no incoming vibration
    * selector: The data of the vibration selector.​[_more information needed_]
    * tick: The game time when the vibration occurs, or -1 if there is no vibration to choose from.​[_more information needed_]
    * event: Candidate game event, with the same structure as the event tag above.​[_more information needed_]

campfire

• Block entity data
  • CookingTimes: How long each item has been cooking, first index is slot 0, etc.
  • CookingTotalTimes: How long each item has to cook, first index is slot 0, etc.
  • Items: List of up to 4 items currently cooking.

chiseled_bookshelf

• Block entity data
  • Items: List of books in the bookshelf.
    * : An item, including the slot tag. The valid slot numbers are 0-5.
  • last_interacted_slot: Last interacted slot (0–5), or -1 if no slot has been interacted with yet.

chest

• Block entity data
  • Items: List of items in this container.
    * : An item, including the slot tag. Chest slots are numbered 0-26, 0 starts in the top left corner.
  • gold: Exists only in the april fools snapshot 23w13a_or_b. Optional. When set to anything but 0, turns the chest into a golden chest.

comparator

• Block entity data
  • OutputSignal: Represents the strength of the analog signal output of this redstone comparator.

command_block

• Block entity data
  • auto: 1 or 0 (true/false) - Allows to activate the command without the requirement of a redstone signal.
  • Command: The command to issue to the server.
  • conditionMet: 1 or 0 (true/false) - Indicates whether a conditional command block had its condition met when last activated. True if not a conditional command block.
  • CustomName: Optional. The name JSON text component of this command block, replacing the usual '@' when using commands such as /[say](/w/Commands/say "Commands/say") and /[tell](/w/Commands/tell "Commands/tell").
  • LastExecution: stores the tick a chain command block was last executed in.
  • LastOutput: The last line of output generated by the command block. Still stored even if the game rule commandBlockOutput is false. Appears in the GUI of the block when right-clicked, and includes a timestamp of when the output was produced.
  • powered: 1 or 0 (true/false) - States whether or not the command block is powered by redstone or not.
  • SuccessCount: Represents the strength of the analog signal output by redstone comparators attached to this command block.
  • TrackOutput: 1 or 0 (true/false) - Determines whether the LastOutput is stored. Can be toggled in the GUI by clicking a button near the "Previous Output" textbox. Caption on the button indicates current state: "O" if true, "X" if false.
  • UpdateLastExecution: 1 or 0 (true/false) - Defaults to true. If set to false, loops can be created where the same command block can run multiple times in one tick.

conduit

• Block entity data
  • Target: The UUID of the hostile mob the conduit is currently attacking, stored as four ints. May not be present.

crafter

• Block entity data
  • crafting_ticks_remaining: Set to 6 when the crafter crafts something.​[_more information needed_]
  • triggered: Set to 1 when it is powered. It is otherwise 0.
  • disabled_slots: Indexes of slots that are disabled.
  • Items: List of items in this container.
    * : An item in the crafter, including the slot tag. Crafter slots are numbered 0-8. 0 starts in the top left corner.
  • Lock: Optional. When not blank, prevents the container from being opened unless the opener is holding an item whose name matches this string.
  • LootTable: Optional. Name of the loot table to use. If this is used in a chest-like container, the loot table generates its content when it is opened. Generating the items in the container removes both loot table tags ( LootTable and LootTableSeed).
  • LootTableSeed: Optional. Seed for generating the loot table. The default value works similarly to the seeds for worlds, where value of 0 or an omitted value causes the game to use a random seed.

creaking_heart

• Block entity data
  • creaking: The UUID of the transient creaking associated with this creaking heart, stored as four ints.

decorated_pot

• Block entity data
  • sherds: List of sherds on this decorated pot.
    * : Item ID of this face. Each value defaults to bricks's ID, and can be either a brick or any sherd.
  • item: The item stored within the pot. A decorated pot does not use Slot to describe its contents, even though it functionally has 1 item slot.

dispenser

• Block entity data
  • Items: List of items in this container.
    * : An item, including the slot tag. Dispenser slots are numbered 0-8 with 0 in the top left corner.

dropper

• Block entity data
  • Items: List of items in this container.
    * : An item, including the slot tag. Dropper slots are numbered 0-8 with 0 in the top left corner.
  • Lunar: Exists only in the april fools snapshot 23w13a_or_b. Optional. When set to any full number from -128 to 127, turns it to a lunar base dropper, and placing light or heavy pressure plate on top of it creates the lunar base structure.

enchanting_table

• Block entity data
  • CustomName: Optional. The name of this container in JSON text component, which appears in its GUI where the default name ordinarily appears.

end_gateway

• Block entity data
  • Age: Age of the portal, in ticks. This is used to determine when the beam is rendered.
  • ExactTeleport: 1 or 0 (true/false) - Teleports entities directly to the exit_portal coordinates instead of near them.
  • exit_portal: Location entities are teleported to when entering the portal. Stored as 3 ints.

furnace

• Block entity data
  • lit_time_remaining: Number of ticks left before the current fuel runs out.
  • cooking_time_spent: Number of ticks the item has been smelting for. The item finishes smelting when this value reaches 200 (10 seconds). Is reset to 0 if lit_time_remaining reaches 0.
  • cooking_total_time: Number of ticks it takes for the item to be smelted.
  • lit_total_time: Represent the total time the furnace should be lit.
  • Items: List of items in this container.
    * : An item in the furnace, including the slot tag:
    Slot 0: The item(s) being smelted.
    Slot 1: The item(s) to use as the next fuel source.
    Slot 2: The item(s) in the result slot.
  • RecipesUsed: Which recipes have been used since the last time a recipe result item was manually removed from the GUI. Used to calculate experience given to the player when taking out the resulting item.
    * recipe ID: How many times this specific recipe has been used. The recipe ID is the identifier of the smelting recipe, as a resource location, as used in the /[recipe](/w/Commands/recipe "Commands/recipe") command.

hanging_sign

• Block entity data
  • is_waxed: 1 or 0 (true/false) - true if the text is locked with honeycomb.
  • front_text: A compound that discribes front text.
    * has_glowing_text: 1 or 0 (true/false) - true if the sign has been dyed with a glow ink sac.
    * color: The color that has been used to dye the sign. The default value is black One of white, orange, magenta, light_blue, yellow, lime, pink, gray, light_gray, cyan, purple, blue, brown, green, red, and black.
    * filtered_messages: Only in Realms. The lines of text shown to players with the profanity filter turned on instead of the regular lines. This tag is automatically set to "" for lines containing blocked words and to the line's normal contents for the other lines when a player with the profanity filter turned off edits the sign, so players with the filter on cannot see the blocked words. If a player with the filter on tries to use blocked words in one or more lines, the line(s) in messages containing blocked words are set to "", which makes them render completely blank, and this tag is also given the same contents. If multiple lines have been edited before the sign editing GUI is closed, only the lines containing blocked words are blanked.
    * messages: A list of text for each line.
    * : Text for each line. Must be Raw JSON text format.
  • back_text: A compound that discribes back text. The same structure as front_text.

The character limit for the Text tags depends on the width of the characters. Although the Text tags are string objects, they should contain JSON text, which are evaluated as compound objects.

hopper

• Block entity data
  • Items: List of items in this container.
    * : An item, including the slot tag.
  • TransferCooldown: Time until the next transfer in game ticks, naturally between 1 and 8 or 0 if there is no transfer.

jigsaw

• Block entity data
  • final_state: The block that this jigsaw block becomes.
  • joint: The joint option value, either "rollable" or "aligned".
  • name: The jigsaw block's name. This jigsaw block gets aligned with another structure's jigsaw block that has this value in the target tag.
  • pool: The jigsaw block's target pool to select a structure from.
  • target: The jigsaw block's target name. This jigsaw block gets aligned with another structure's jigsaw block that has this value in the name tag.
  • selection_priority: Priority of this jigsaw block being selected for generation. Jigsaw blocks with higher selection priority get selected first.
  • placement_priority: Priority of the piece generated by this jigsaw block to place its children. Pieces with higher placement priority generate their children first.

jukebox

• Block entity data
  • RecordItem: The item, without the Slot tag.
  • ticks_since_song_started: The number of ticks since the song started playing. Automatically stops the sound event of the song once it reaches the song's length in ticks, and controls when particles are created. Does not exist when there is no song playing or no item.

lectern

• Block entity data
  • Book: The book item, without the slot tag, currently on the lectern, may not exist.
  • Page: The page the book is currently on, starting from 0, does not exist if there's no book. Value is clamped between 0 and the last page - 1.

piston

• Block entity data
  • blockState: The moving block represented by this block entity.
  • extending: 1 or 0 (true/false) – true if the piston is extending instead of withdrawing.
  • facing: Direction that the piston pushes (0=down, 1=up, 2=north, 3=south, 4=west, 5=east).
  • progress: How far the block has been moved. Starts at 0.0, and increments by 0.5 each tick. If the value is 1.0 or higher at the start of a tick (before incrementing), then the block transforms into the stored blockState. Negative values can be used to increase the time until transformation.
  • source: 1 or 0 (true/false) – true if the block represents the piston head itself, false if it represents a block being pushed.

sculk_catalyst

• Block entity data
  • cursors: List of sculk charge clusters associated with the sculk catalyst.
    * : A sculk charge cluster. Each cluster is stored within a single sculk block.
    * charge: How many sculk charges are being carried in the cluster.
    * pos: List of three integers representing the coordinates of the cluster.
    * decay_delay: 1 or 0 (true/false) - Not to be confused with updatedelay. This controls the decay of the cluster. If this is true, then the cluster was spread from a sculk block or sculk vein, and this cluster can only spread to sculk, sculk veins, and blocks with the sculk_replaceable tag set to true. If this is false, then all the sculk charges disappear when the cluster discharges to a block that is not in the sculk family.
    * update_delay: Delay in game ticks until the cluster begins to discharge (or travel) after being created. Usually starts at 1 game tick when a cluster discharges to a new block.
    * facings: If the block to replace is an air or water block, the block is replaced with sculk veins, and the faces where the sculk veins are placed are also stored in their block state. The sculk veins never grow directly on the faces of a sculk block. The same thing is done to any air or water blocks that are adjacent to blocks that are adjacent to this sculk block, if sculk veins can't grow in the blocks adjacent to this sculk block without growing directly on the faces of sculk blocks.

sculk_sensor

• : Block entity data.
  • last_vibration_frequency: The frequency of the last vibration.
  • listener: The vibration event listener for this sculk shrieker, sculk sensor, or calibrated sculk sensor.
    * event: Exists only if there is an incoming vibration.
    * distance: The distance between this vibration's source and the block.
    * game_event: The resource location of the vibration event that caused the current incoming vibration.
    * pos: The coordinates of the source of this vibration.
    * : X coordinate.
    * : Y coordinate.
    * : Z coordinate.
    * projectile_owner: If the vibration was caused by a projectile, this is the UUID of the entity that launched the projectile. Does not exist if vibration was not caused by a projectile.
    * source: The UUID of the entity that caused the vibration. Does not exist if vibration was not caused by an entity.
    * event_delay: How many ticks remain until triggered by the vibration. Set to 0 if there is no incoming vibration
    * selector: The data of the vibration selector.​[_more information needed_]
    * tick: The game time when the vibration occurs, or -1 if there is no vibration to choose from.​[_more information needed_]
    * event: Candidate game event, with the same structure as the event tag above.​[_more information needed_]

skulk_shrieker

• : The block entity's root tag.
  • VibrationListener: The vibration event listener of the sculk shrieker, sculk sensor, and calibrated sculk sensor.
    * event: Unknown.
    * pending: Unknown.
    * distance: Unknown.
    * source: Unknown.
    * vibration: Unknown.
    * x: Unknown.
    * y: Unknown.
    * z: Unknown.
    * selector: Unknown.
    * ticks: Unknown.

shulker_box

• Block entity data
  • Items: List of items in this container.
    * : An item, including the slot tag. Shulker box slots are numbered 0–26, 0 starts in the top left corner.

sign

• Block entity data

  • is_waxed: 1 or 0 (true/false) - true if the text is locked with honeycomb.
  • front_text: A compound that discribes front text.
    * has_glowing_text: 1 or 0 (true/false) - true if the sign has been dyed with a glow ink sac.
    * color: The color that has been used to dye the sign. The default value is black One of white, orange, magenta, light_blue, yellow, lime, pink, gray, light_gray, cyan, purple, blue, brown, green, red, and black.
    * filtered_messages: Only in Realms. The lines of text shown to players with the profanity filter turned on instead of the regular lines. This tag is automatically set to "" for lines containing blocked words and to the line's normal contents for the other lines when a player with the profanity filter turned off edits the sign, so players with the filter on cannot see the blocked words. If a player with the filter on tries to use blocked words in one or more lines, the line(s) in messages containing blocked words are set to "", which makes them render completely blank, and this tag is also given the same contents. If multiple lines have been edited before the sign editing GUI is closed, only the lines containing blocked words are blanked.
    * messages: A list of text for each line.
    * : Text for each line. Must be Raw JSON text format. The character limit for the Text tags depends on the width of the characters.
  • back_text: A compound that discribes back text.
    * The same structure as front_text.

• Block entity data

  • GlowingText: 1 or 0 (true/false) - true if the sign has been dyed with a glow ink sac.
  • Color: The color that has been used to dye the sign. The default value is "black". One of "white", "orange", "magenta", "light_blue", "yellow", "lime", "pink", "gray", "light_gray", "cyan", "purple", "blue", "brown", "green", "red", or "black".
  • Text1: First row of text.
  • Text2: Second row of text.
  • Text3: Third row of text.
  • Text4: Fourth row of text.

skull

• Block entity data
  • custom_name: Optional. The custom name of the skull.
  • note_block_sound: Optional. The sound event this skull plays when played with a note block.
  • profile: Information about the owner of this player head. If defined as a string, corresponds to name.
    * name: The name of a player profile, i.e. its username. If this is the only tag provided, it resolves into the other ones below. Optional.
    * id: The UUID of the owner. Used to update the other tags when the chunk loads or the holder logs in, in case the owner's name has changed. Optional.
    * properties: A list of properties. Optional.
    * : A single property.
    * name: The name of the property. Can be textures.
    * value: The texture data, encoded in base64.
    * signature: The signature. Optional.

smoker

• Block entity data
  • lit_time_remaining: Number of ticks left before the current fuel runs out.
  • cooking_time_spent: Number of ticks the item has been smelting for. The item finishes smelting when this value reaches 200 (10 seconds). Is reset to 0 if lit_time_remaining reaches 0.
  • cooking_total_time: Number of ticks it takes for the item to be smelted.
  • lit_total_time: Represent the total time the furnace should be lit.
  • Items: List of items in this container.
    * : An item in the furnace, including the slot tag:
    Slot 0: The item(s) being smelted.
    Slot 1: The item(s) to use as the next fuel source.
    Slot 2: The item(s) in the result slot.
  • RecipesUsed: Which recipes have been used since the last time a recipe result item was manually removed from the GUI. Used to calculate experience given to the player when taking out the resulting item.
    * recipe ID: How many times this specific recipe has been used. The recipe ID is the identifier of the smelting recipe, as a resource location, as used in the /[recipe](/w/Commands/recipe "Commands/recipe") command.

soul_campfire

• Block entity data
  • CookingTimes: How long each item has been cooking, first index is slot 0, etc.
  • CookingTotalTimes: How long each item has to cook, first index is slot 0, etc.
  • Items: List of up to 4 items currently cooking.

structure_block

• Block entity data
  • author: Author of the structure; only set to "?" for most vanilla structures.
  • ignoreEntities: 1 or 0 (true/false): Whether entities should be ignored in the structure.
  • integrity: How complete the structure is that gets placed.
  • metadata: Value of the data structure block field.
  • mirror: How the structure is mirrored, one of "NONE", "LEFT_RIGHT" (mirrored over X axis when not rotated), or "FRONT_BACK" (mirrored over Z axis when not rotated).
  • mode: The current mode of this structure block, one of "SAVE", "LOAD", "CORNER", or "DATA".
  • name: Name of the structure.
  • posX: X-position of the structure.
  • posY: Y-position of the structure.
  • posZ: Z-position of the structure.
  • powered: 1 or 0 (true/false): Whether this structure block is being powered by redstone.
  • rotation: Rotation of the structure, one of "NONE", "CLOCKWISE_90", "CLOCKWISE_180", or "COUNTERCLOCKWISE_90".
  • seed: The seed to use for the structure integrity, 0 means random.
  • showboundingbox: 1 or 0 (true/false): Whether to show the structure's bounding box to players in Creative mode.
  • sizeX: X-size of the structure, its length.
  • sizeY: Y-size of the structure, its height.
  • sizeZ: Z-size of the structure, its depth.

suspicious gravel

• Block entity data
  • LootTable: Optional. Loot table to be used to generate the hidden item when brushed.[note 1]
  • LootTableSeed: Optional. Seed for generating the loot table. 0 or omitted use a random seed.[note 1]
  • item: The item in the block. May not exist.
    * See item format.

1. ↑ a b Both loot table tags are removed once the items have been generated.

suspicious_sand

• Block entity data
  • LootTable: Optional. Loot table to be used to generate the hidden item when brushed.[note 1]
  • LootTableSeed: Optional. Seed for generating the loot table. 0 or omitted use a random seed.[note 1]
  • item: The item in the block. May not exist.
    * See item format.

1. ↑ a b Both loot table tags are removed once the items have been generated.

trapped_chest

• Block entity data
  • Items: List of items in this container.
    * : An item, including the slot tag. Chest slots are numbered 0-26, 0 starts in the top left corner.
  • gold: Exists only in the april fools snapshot 23w13a_or_b. Optional. When set to anything but 0, turns the chest into a golden chest.

trial_spawner

• Block entity data
  • required_player_range: Between 1 and 128. Defaults to 14. — Maximum distance in blocks for players to join the battle.
  • target_cooldown_length: Defaults to 36000. — Time in ticks of the cooldown period. Includes the time spend dispensing the reward.
  • normal_config: Optional, see configuration for defaults. — The configuration to use when not ominous.
  • ominous_config: Optional, defaults to normal_config. When individual entries are omitted, they also default to their setting in normal_config. — The configuration to use when ominous.
    The following fields are used to keep track of the current state of the trial spawner.
  • registered_players: A set of player UUIDs. — All the players that have joined the battle. The length of this array determines the amount of mobs and amount of reward.
    * : A UUID.
  • current_mobs: A set of mob UUIDs. — The mobs that were spawned by this spawner and are still alive.
    * : A UUID.
  • cooldown_ends_at: Gametime in ticks when the cooldown ends. 0 if not currently in cooldown.
  • next_mob_spawns_at: Gametime in ticks when the next spawn attempt happens. 0 if not currently active.
  • total_mobs_spawned: The total amount of mobs that have already been spawned in this cycle. 0 if not currently active.
  • spawn_data: The next mob to attempt to spawn. Selected from spawn_potentials after the last attempt. Determines the mob displayed in the spawner.
  • ejecting_loot_table: A resource location to the loot table that is given as reward. Unset if not currently giving rewards. Selected from loot_tables_to_eject after all mobs are defeated.

vault

• Block entity data
  • config: Configuration data that does not automatically change. All fields are optional.
    * loot_table: A resource location to the loot table that is ejected when unlocking the vault. Defaults to "minecraft:chests/trial_chambers/reward".
    * override_loot_table_to_display: A resource location to the loot table that is used to display items in the vault. If not present, the game uses the loot_table field.
    * activation_range: The range in blocks when the vault should activate. Defaults to 4.
    * deactivation_range: The range in blocks when the vault should deactivate. Defaults to 4.5.
    * key_item: The key item that is used to check for valid keys. Defaults to "minecraft:trial_key".
  • server_data: Data that is only stored on the server.
    * rewarded_players: A set of player UUIDs that have already received their rewards from this vault.
    * state_updating_resumes_at: The game time when the vault processes block state changes, such as changing from unlocking to ejecting after a delay.
    * items_to_eject: List of item stacks that have been rolled by the loot table and are waiting to be ejected.
    * : An item stack
    * total_ejections_needed: The total amount of item stacks that need to be ejected.
  • shared_data: Data that is synced between the server and client.
    * display_item: The item that is currently being displayed.
    * connected_players: A set of player UUIDs that are within range of the vault.
    * connected_particles_range: The range in blocks when the vault emits particles.

Tile tick format[edit | edit source]

Tile Ticks represent block updates that need to happen because they could not happen before the chunk was saved. Examples reasons for tile ticks include redstone circuits needing to continue updating, water and lava that should continue flowing, recently placed sand or gravel that should fall, etc. Tile ticks are not used for purposes such as leaf decay, where the decay information is stored in the leaf block data values and handled by Minecraft when the chunk loads. For map makers, tile ticks can be used to update blocks after a period of time has passed with the chunk loaded into memory.

• A Tile Tick
  • i: The ID of the block; used to activate the correct block update procedure.
  • p: If multiple tile ticks are scheduled for the same tick, tile ticks with lower p are processed first. If they also have the same p, the order is unknown.
  • t: The number of ticks until processing should occur. May be negative when processing is overdue.
  • x: X position
  • y: Y position
  • z: Z position

ToBeTicked format[edit | edit source]

This List is always present, and contains 16 Sublists, each representing one of the "sections" of the chunk. Those inside lists may contain Shorts, each representing a packed coordinate relative to the section : The 4 most significant bits are always 0, then each group of 4 bits (or nibble) represents a section-relative coordinate, from 0 to 15. The order of sections in the list appear to be ordered from bottom to top, and the packing order of the coordinates is 0ZYX, where 0 refers to the chunk section. When converting proto-chunks to full chunks, only coordinates that are stored in PostProcessing appear to receive a tick update, tick updates stored in block_ticks, and fluid_ticks are ignored. [_verify_]

History[edit | edit source]

This section needs to be updated.

Please update this section to reflect recent updates or newly available information.
Reason: This history section is missing a significant number of changes, including most of the 1.13 changes, mainly the region file format.

References[edit | edit source]

Navigation[edit | edit source]