Java Edition:Item Duplication Methods
To do: Bug references and links can be added
Item duplication methods are glitches that permit an item to be replicated. These techniques are so powerful they are often regarded as cheating when used on normally obtainable items because it quickly makes all resources abundant and removes many challenges of survival. Despite this sentiment, the methods are completely possible in vanilla survival Minecraft and so are still vanilla techniques. While a glitch, item duplication by itself does not constitute as a discontinued feature. Item duplication is a potential discontinued feature when considering nonrenewable resources.
Why a Discontinued Feature?
Item duplication can be a discontinued feature because it will allow more nonrenewable resources than possible. Nonrenewable resources are the items that exist in only a limited amount in each world. The main cause of their existence is that they can only be created from world generation but some other examples, such as the dragon egg are due to other reasons. The dragon egg is the most extreme example because there can only be 1 per world. The dragon egg quantity of a world can exceed this limit using item duplication (or entity duplication).
General Item Duplication Methods
Understacked Items
Understacked items were obtainable from Indev 0.31 20100125-1 to 1.10.2 through various methods (see understacked items page for specifics). Understacked items can be used to duplicate items. With an understacked item stack, the player can pick it up and right click on other slots to decrease the stack and create new items. The check to remove the item stack was at zero and not less than zero (because negative is normally impossible) and so the stack could continue decreasing until it got to -128. At -129 the stack will underflow to 127 which will cause the item to be overstacked.
Chest Save Fail
In Infdev 20100327, chests and other block entities do not save their contents unless the chunk is updated. This can be used to duplicate items by taking the items out of a chest, logging out without updating the chunk, and logging back in. The items will save in your inventory, but the chest will not save, therefore duplicating them.
Unloaded Minecart Duplication
In Infdev 20100618 minecarts were used as containers, essentially being an early version of the chest minecart. By opening the minecarts inventory and moving the minecart out of the players render distance while it is open, the player would be able to take items out of the minecart without its inventory updating, doubling the items.
Chest Triple-Click Duplication
Between versions Alpha Server 0.2.0[test] and Alpha Server 0.2.8[test], if you hover with an item in a chest, and then triple-left-click it really fast (slower if there is lag), it will multiply the number of items in that stack by 2. However, if you have the wrong timing or if you accidentally quadruple-click, you might lose the entire stack. If you left-click, then right-click, and then left-click, it only multiplies the number of items in the stack by 1.5, however, you can only lose half the stack if you do it wrong.
Alt + F4 Method
Since Infdev 20100327[test] all the way until release 1.15[test] there existed a single-player exclusive method of general item duplication called the alt + F4 method. This method involves dropping the items you want to duplicate, and then saving and quitting. You would then reload the world, pick up the items and press the keyboard shortcut to close the window. Then relaunch the game and reload the world. The items should then be duplicated.
This method works because player data is saved when alt f4'ing out of the game but world data is not. So when you pick up the blocks you want to duplicate and exiting the game, the game remembers the blocks that appeared in your inventory, but it does not remember that the blocks disappeared from the world.[1]
Ender Pearl Disconnect
From Beta 1.9 Prerelease 2 to 12w24a (1.3 snapshot) there was a multiplayer exclusive method of duplication utilizing an ender pearl. The method worked by throwing an ender pearl in a server with less than 3 hearts[2] and then quitting before the ender pearl lands. When the ender pearl lands it will drop whatever items were in the player's inventory when they left on the ground. This will result in the death message "<player name> hit the ground too hard", however the player will not die (whether they log back in before or after the ender pearl lands) and they will still have the items in their inventory.
Single Hopper
This method works from 13w01b to 13w01b. The glitch involves landing an item on the edge of a hopper, easiest way is to use a water stream. This will cause the hopper to suck in items while leaving the dropped item sitting on top of the hopper thus duplicating it.[3]
Delayed Chest Explosion
In the multiplayer version of 13w01a, items placed into a chest can be duplicated by first unloading those chunks (or waiting for an autosave). Once the chest has been saved, the player can then ignite a TNT, before the TNT explodes the player needs to open the chest and take out the items. Once the chest is blown up, the game will crash and upon loading back into the world, the world will have rolled back to before the TNT ignited while the player still holds the items from the chest.
Dual Hopper
This method works in 13w01b. The mechanics of this duplication are quite complicated, but here is the most efficient method: place 2 hoppers next to each other, drop a stack of item on top of them, now collect stacks from hopper one by one without using ⇧ Shift, ⇧ Shifting breaks it.
Hopper Item
Donkey Duplication
This duplication method works in release 1.6.1 and from 19w8a until 20w16a. You need a tamed donkey or llama equipped with a chest. If a player shift-clicks the donkey or llama, that player may view the donkey's inventory and place items. If a second player rides the donkey, the first player will continue to view the donkey's or llama's inventory, even though it is not normally possible to view a donkey's inventory when it is already being ridden by a player. If the second player disconnects, the donkey will disappear along with them, and the donkey's inventory will be considered by the game as part of that player's data. However, the game will keep a copy of the donkey's inventory and GUI temporarily loaded for the first player, who can then reclaim the items. When the second player reconnects, the donkey's inventory will contain what was originally in it before the second player disconnected. The items can once again be taken from the donkey's inventory, resulting in a duplication method.
Hopper/Chest Minecart Duplication
From 15w39a to 15w39c, unloading a hopper or chest minecarts and reloading it would cause its items to be thrown out on to the floor yet the minecarts contents remain. This is due to a duplicate UUID bug and it may take at least one unload for the minecarts to have duplicate UUIDs.
Chunk Memory Overflow Method
This method uses the chunk resetting method. The methods for overflowing a chunk memory are described on the respective page but this method allows for item duplication. The player must follow these steps to duplicate using this method:
- Put the desired items to be duplicated within a chunk
- Save this chunk by a nether portal, going far away to unload it, waiting for an autosave, or saving & quitting the world
- Return to the chunk
- Savestate the chunk
- Take items out of the chunk into player inventory or container outside that chunk
- Unload the chunk
- Return to chunk and the savestate with the items will be loaded
Crafting Book Methods
Dropping Method
From 17w17a (1.12 snapshot) to 1.12, the crafting table could duplicate and overstack items. The method worked by dropping the item desired to be duplicated than spamming the autofill recipe in the recipe book.
In 17w14a, clicking on available recipe in crafting book then clicking on unavailable recipe and again on available recipe duplicates items that are required to craft the available recipe.[4]
Drowned Conversion Method
This method which lasted from 1.13 until 1.14.3 exploited the fact that zombies can transform into drowned while they are dying. If you coax a zombie into picking up an item by throwing one at it and then kill it right at the moment that it converts to a drowned, the zombie will die and drop what it was holding but the newly spawned drowned will be holding a duplicate of the item. This can also work with husks transforming into zombies.
Baby Piglin Method
Give a baby piglin a item and a gold ingot. While the baby piglin is observing the gold, kill the piglin. The item will duplicate. This works in versions 1.16 - 1.16.2.[5]
Item Frame on Piston
In version 1.12.2 removing an item from an item frame as a piston was retracting will dupe the item
Bundle Stack Dupe
In the first 1.17 snapshot 20w45a, you could create stacked bundles that could be filled with items and then split into separate bundles. To get the stacked bundles you fill a bundle with empty bundles and fill all other slots with items and attempt to empty the bundle. Once the bundles fall on to the ground they will be stacked, simply put items in the stacked bundles and separate them into single bundle stacks. This method also works in later versions if the player kept overstacked bundles from 20w45a.
In later versions the player is unable to place an overstacked item into an inventory slot, to circumnavigate you can prepare two or more single bundles that hold a 15 bundle stack to be updated. To duplicate more bundles the player can right-click the single bundle stack to get a 15 bundle stack on their cursor they can then use the 15 bundle stack to store a single bundle holding a 15 bundle stack (if the bundle held 16 bundles it wouldn't be able to be put into another bundle) and then split up the bundle stack on the cursor into multiple single bundle stacks and collect the newly duplicated single bundle stacks containing a 15 stack bundle.
Bundle Crafting Dupe
In the first 1.17 snapshot 20w45a up to 20w46a, you can put a crafting recipe in a crafting grid and use the bundle to take items out of the crafting grid without updating the crafting output.
Bundle or Shulker Box Incineration
20w51a (1.17 snapshot) added the function that when a bundle or shulker box was destroyed all the items inside of it would explode out. This resulted in two very similar duplication methods that occur when incinerating them. Shulker boxes and bundles duplicate items when destroyed by two fire blocks simultaneously.[6] Shulker boxes and bundles drop their items twice when thrown into a lava cauldron.[7] One method involved throwing the container in two fire blocks at the same time, right between the two. The other method involved throwing the container in a cauldron containing lava. This works best on the fire-resistant items of netherite because they can't be destroyed after being thrown in. It is possible to recuperate other items before they burn as well to duplicate them using this method.
End Portal Duplication
This method is technically entity duping, but allows for duping any given item. [8]
Anvil Dupe
Works from 1.17[test]-1.17.1 pre 1. Get an Anvil to the most broken state. Place in the item or shulker you want to dupe into the first slot and fill your entire inventory so there are no empty slots. Rename the item or enchant it, and take the item. If the anvil broke, you'll drop the item twice, thus duplicating it.
Dolphin Dupe
Disconnection of Duplicated Item Instance
From 1.12.2[test] to 21w43a update suppression can be used to duplicate instance of an item, which can be used to duplicate items.
Playerdata Duplication
Tested version range: 13w16b - 1.19 (This probably works on most versions with servers/LAN). You can duplicate the playerdata (and therefore items) from one player to another by abusing a combination of singleplayer and a (LAN) server. You need at least two accounts for this method. Start by opening and closing the singleplayer world on account 1. Afterwards, open the singleplayer world on account 2. You succesfully duplicated playerdata. Now open a (LAN) server and connect with both accounts. You will see both accounts will have the exact same inventory, potion effects and location.
Dupehack
In the April Fools' version 23w13a_or_b, the dupehack item could be used to duplicate items. This intentional feature was obtainable by enabling the "Set chance of dupe hack occuring to <NUMBER>%" (dupe_hack_occurrence_chance
) vote and killing an entity with a chest.[test]
Task Manager Method
From 22w03a (1.18.2 snapshot) to 25w06a (present), you can duplicate items using the following simple method; have the items you want to duplicate in your inventory, then save and quit to title, re-enter the world and then open a container and shift click the items into it, then click end task in task manager to close Minecraft. This is only possible in singleplayer, and cannot be done using alt+f4. Once you re-enter the world, the items will both be in your inventory and the container.
Specific Item Duplication Methods
Oak Door
In Infdev 20100607, placing a door on top of a non-opaque blocks causes two oak doors to drop. This method also includes slabs, signs, torches, ladders, oak saplings, and oak leaves.
Amethyst
In 20w45a moving an amethyst cluster on slime blocks will drop amethyst shards but keep the clusters on the slime blocks.
Barrel
From 21w11a to 21w13a, when taking items out of a barrel right before TNT blows it up, then it will drop as an item and be harvestable as well, resulting in x2 duplication.[9].
Candle
From 20w45a to 20w49a (1.17 snapshots) right-clicking a cake that has a candle on it while having full hunger will dupe the candle.[10]
Crimson & Warped Door
In 20w06a (1.16 snapshot), the new crimson and warped doors would drop two items when broken.[11] Fast farms for their duplication could be created by placing the doors onto trapdoors that were on a 1 tick clock that continually opened the trapdoors and broke the doors on top.
Items with Block Forms
In 13w01a (1.5 snapshot), you can duplicate minerals by placing some of them into a crafting table along with the associated mineral block and picking up one of the minerals and double clicking the mineral into your inventory. This should result in you have 9 more than you started. The glitch can be preformed with iron, gold, diamonds, emeralds, and redstone.[12]
Pointed Dripstone
Rails and Carpets
From 1.12.2 to 25w06a (present) rails and carpet can be duped with a simple piston machine. There are slight differences between versions.
Shield
In 20w07a and 20w08a giving a piglin a shield and then killing it results in it dropping 2 shields.[15]
Shulker Box
In 17w18a, placing shulker box underneath the lever or button duplicates the shulker (you are left with empty shulker box in your inventory).[16] This does not duplicate contents of the shulker box.
String
From 14w25a to 1.8-pre3 string could be duped with simple slime block contraption.
Tipped Arrows
In 15w31a, shooting any tipped arrow (except "Water Bottle" arrow and spectral arrow) while having more of the same type of arrow in the inventory and than picking it up from the ground will duplicate the arrow.[17] Shooting "Water Bottle" arrow will consume the arrow and after picking it up, you will obtain regular arrow instead of "Water Bottle" arrow.[18]
Trapdoor
Iron or wooden trapdoors pop off as items when powered in 14w25a (1.8 snapshot).[19] They are often destroyed by redstone power but will drop two items in that case. Occasionally[test], a trapdoor will be resistant to breaking and therefore can be used for quicker duplication by powering it with a clock/lever rapidly.
Tripwire Hook
From 1.15.2 to 1.18.1 (present) [test], placing at least two tripwire hooks on opened trapdoors facing each other, string between them and stepping on the string will dupe tripwire hook facing east or north. [20]
Lead
Bees
From 19w34a to 19w35a (1.15 snapshots), the bug allowing beehives with a leashed bee can be used to duplicate leads.[21] When the leashed bee enters the beehive/bee nest the lead will pop off but when it comes out the bee will still be leashed to the player and so once that is broken the player will have two leads.
End Portal
From 14w31a (1.8 snapshot) to 19w04a (1.14 snapshot), all leashed mobs that would go through end portal will drop two leads upon entering different dimension instead of one.[22] This method works with all leashable mobs and it works when entering/leaving end.
Wither Skeleton Skull
In 18w30b, placing wither skeleton skull crashes the game and it fails to place.[23] However placing it with dispenser crashes the game but dispenses invisible wither skeleton skull with outline. This doesn't consume wither skeleton skull in dispenser but breaking dispensed wither skeleton skull drops nothing, however placing hopper under it or changing versions makes it normal, so breaking it actually drops.[24]
Items That are Required to Craft Items that Have 2 or More Recipes/same id Items with the same Recipe
In 17w14a, all items that are required to craft items that have 2 or more recipes to craft them/items that can be crafted into items with same id by same recipe can be duplicated by opening "click for more recipes" menu in recipe book and hovering in it between available recipe and unavailable recipe.[25] By this method all these items can be duplicated:
- stick
- wool (all types, including bone meal, inc sac, cocoa beans)
- gravel
- sand
- dye
- glass (all types)
- planks (all types)
- flowers (all types)
- iron/gold blocks
- iron/gold nuggets
- beetroot
Chunk Regeneration Loot Dupe
Chunk regeneration allows for duping chest loot found in structures.
Bonus Chest Dupe
From 22w03a (1.18.2 snapshot) to 25w06a (present), it is possible to cause multiple bonus chests to generate in a world. When you first load a world, you can close the game with task manager, then when you reload the world an additional bonus chest will generate. You can repeat this infinitely. This will no longer work once the world autosaves or you pause, since from now on the world will remember that it has already generated a bonus chest. The loot in every additional bonus chest will always be different.
Armor Stand
From 14w32a to 15w32c, destroying an armor stand would occasionally drop more than one.[26]
Notes
- This article doesn't include infinite villager trading (sticks and emeralds) as it's intended.
See also
References
- ↑ This is also possible on a server by running from a run.bat file, stopping it and closing it immediately. This is way more consistent. Possible on 12w41a [test]
- ↑ This is low enough health to cause death from an ender pearl with no Protection, Feather Falling or other armor may require a lower health to work.
- ↑ MC-5998. bugs.mojang.com.
- ↑ MC-115436. bugs.mojang.com.
- ↑ A YouTube video
- ↑ MC-208611. bugs.mojang.com.
- ↑ MC-208666. bugs.mojang.com.
- ↑ A YouTube video
- ↑ MC-220066. bugs.mojang.com.
- ↑ MC-203568. bugs.mojang.com.
- ↑ MC-170852. bugs.mojang.com.
- ↑ MC-5845. bugs.mojang.com.
- ↑ MC-206682. bugs.mojang.com.
- ↑ MC-206613. bugs.mojang.com.
- ↑ MC-172486. bugs.mojang.com.
- ↑ MC-116976. bugs.mojang.com.
- ↑ MC-82859. bugs.mojang.com.
- ↑ MC-82813. bugs.mojang.com.
- ↑ MC-56952. bugs.mojang.com.
- ↑ Tripwire Hook Dupe (Minecraft Java) by EagleEye621 youtube.com
- ↑ MC-159441. bugs.mojang.com.
- ↑ Discussion on Discord about lead dupe (end portal method)
- ↑ MC-134967. bugs.mojang.com.
- ↑ Discussion on Discord about wither skeleton skull dupe
- ↑ MC-115423. bugs.mojang.com.
- ↑ MC-65699. bugs.mojang.com.