Tutorial:Block and item duplication

This page uses a bug to make a contraption or demonstrate a game mechanic.

 

Bugs of this nature may be fixed at any time without warning, causing the contraption to stop working. Bug exploits may be disallowed on some multiplayer servers and lead to a ban if used.
Use at your own risk.

This page seeks to teach you how to clone items and blocks without building a separate farm for them, in vanilla Survival mode. It can be treated as an "everything farm," since it can "farm" things that can't normally be farmed, like block of diamonds, dragon eggs and other non-renewable blocks.

If any of these do get patched, you must either go back versions or use third-party applications in order to replicate them again. For Java Edition, this can happen in the Minecraft Launcher, but on Bedrock Edition, you must use third party applications in order to replicate these again. These third-party applications are NOT owned or endorsed by Mojang, so use at your own risk.

Note that these techniques are considered "cheating" by many people and Mojang tries to remove the ability to duplicate in Survival during almost every update, except for primed TNT duplication, which has been left in on purpose until a suitable replacement exists. On many servers, duping inventory items is a bannable offense.

The best way to duplicate a block is to turn it into an item first, then duplicate the item. However, there are other ways to duplicate the blocks themselves, though they only work for certain blocks. Shulker boxes make item duplication much easier because they allow for up to 1,729 items to be cloned at once (including the shulker box).

Background

Why duplicate

• Duplicate your most valuable gear: if you lose them to lava or the Void, you can just pull a backup from your backup chest! More specifically, you make a duplicate from your backup, so you can go through the entire process if you lose them again.
• Duplicate Enchanted Books / Diamonds / Ancient Debris / Netherite Ingots / Emeralds: Once you have one, you'll have an infinite amount by duplicating it. Again, it is important to leave some stock as backup; you never know if you need more.
• Duplicate Enchanted tools / Blocks: You'll never have to worry about running out of your tool / block of choice, since you can just duplicate them as well. Duplicate in bulk for items/blocks that will be used in large quantities.
• Duplicate Shulker Boxes (with items inside): theoretically you can duplicate both the shulker box and the items it contains, since that info is stored within the shulker box itself. Use this to duplicate blocks in excessive quantities.
• Duplicate Enchanted Equipment: combined with a grindstone, you can farm an infinite amount of EXP by removing enchantments from duplicated enchanted gear. While a decent, safe and consistent method of getting exp, building an Enderman Farm is faster.
• Griefing servers (not endorsed): Item duplication is sometimes used to inflate a server's economy by duplicating valuable items and distributing them to other players. This type of behavior is most notably used against pay-to-win servers that sell in-game items or other advantages for real money. This is considered cheating and can get you banned on the server in question. In addition, most duplication glitches are patched using third-party plugins.

If you happen to be a speedrunner, duplication allowed in glitched categories can cut down a lot in your game time. One extreme example is the TAS Any% speedrun done in 29.19, complete with the dragon dead. Alt+F4 is usually used for this purpose.

How to use this guide

This guide is in the process of restructuring. When it's done, all methods will have something like this in front:

Java version range	Mod patched?	Realms
1.x.x ~ 1.x.x	Paper x.x.x build #xxx	Yes

Bedrock version range	Realms
1.x.x ~ 1.x.x	Yes

These tables are there to save you some time with testing no longer useful methods.

Why do we care about mods? Although we, being the official wiki, do not endorse the use of mods, mods are a fact of life we must accept. Servers commonly use them to fix the very glitches we are talking about here and, by some tweaking of the game, do whatever the server owner wants the game to do.

• Spigot is one of the modded server softwares you will bump into. They are mostly focused on performance, but do fix a glitch or two from time to time.
• Paper is a server software that branched off Spigot. They too care about performance, but they take out glitches with a burning hatred. They even killed TNT duplication!

Why single out Realms? Realms works a bit differently from your normal multiplayer server, Java or Bedrock. As a result, different glitches may occur.

Legitimate Duplication

These are not actually duplicating items, but instead are legitimate (or mostly legitimate) methods of obtaining certain items.

Dirt Duplication

Start by obtaining at least 2 dirt and gravel from bartering. Next, craft coarse dirt using 2 dirt and 2 gravel for 4 coarse dirt, then till the dirt and mine it to obtain 2 extra dirt. With a bartering farm, a good hoe, and a good shovel, you can mass produce dirt in a matter of minutes. However, this is not perfect duplication, as you will need a constant supply of gravel.

Bone Meal Duplication

By using bone meal and composting the yield, the player gets bone meal back. Usually, this method yields significantly less bone meal than is used, and is therefore not profitable, but the following methods do duplicate bone meal:

• Using bone meal on a moss block and composting the blocks produced.
  • The player should leave a moss block uncomposted, to repeat the cycle.
  • In Bedrock Edition, the azaleas can be further grown into azalea trees, and one then composts the leaves. Again, this is less effective in Java Edition, due to the 45% success rate of bone meal.
• Using bone meal on a sapling, azalea, mangrove propagule, mushroom, or fungus, and composting the blocks created.
  • This is less effective in Java Edition, since it generally takes multiple bone meal to grow a single tree/huge mushroom/huge fungus.
  • In Bedrock Edition, this method is most effective for trees that have a lot of leaves, such as cherry.
  • For mangroves, the player must use bone meal to create and grow a propagule.
  • For trees, the player must break some of the leaves, preferably with a Fortune III hoe, to replenish saplings. Similarly, for huge mushrooms, the player must break some of the mushroom blocks, which have a significantly higher drop rate than leaves, but Fortune does not work.
  • For azalea trees and huge fungi, the player must obtain azaleas and fungi, respectively, preferably using the methods above.

Void Trading

This feature is exclusive to Java Edition.

 

"Void trading" is a way to trade with villagers and wandering traders without restocking. To do that, a player unloads the villager before closing the trading interface, so that the villager never "remembers" having been used for trading. Infinite trading is good for turning farmed items such as Sticks from a Bamboo farm into emeralds, or for buying things.

A few ways are possible:

• The original "void trading" involves going out into The End. By setting up a villager trading hall on the end of one End gateway, the player can leave instantly and unload the villager. When the player comes back, the villager would have not remembered the trade.
• The rail-based method uses powered rails to leave the simulation range and can be set up in the overworld. See "Minecraft Elegance: Voidless Void Trading (Java 1.17-1.19)" – ianxofour on YouTube.
• The multiplayer method uses two players logging in and out to do the trading. See "1.16.4 PaperMC & Spigot Multiplayer Infinite Villager Trades Exploit! (Currently Unpatched)".

Java Edition

Currently, work as of the latest release of vanilla Minecraft. They may be patched in modified servers (such as Spigot, or Paper), which many servers use, but have been tested and they still work in unmodified conditions. In singleplayer, these will work but in multiplayer, these will usually not work.

Singleplayer

Basic save file manipulation

This method is safe and reliable; it only requires the items to be duplicated and a chest. You need to have access to save files, so this is impractical on servers, where admins don't give out FTP like candy.

1. Have the desired items to be duplicated on you, either in your inventory, on your hotbar, or equipped.
2. Exit and save the game. Returning to the main menu is quickest.
3. Navigate to your save folder. In Windows, it's at %appdata%\.minecraft\saves. In MacOS, it's at ~/Library/Application Support/minecraft/saves. In Linux, it is located at ~/.minecraft/saves.
   1. Making a backup folder of the target world folder is advised but not required.
4. Open the target world folder and duplicate the level.dat and level.dat_old files.
   1. You should keep the duplicates in a place that is easy to access, usually the world save folder itself. This especially applies if you plan to duplicate items multiple times.
   2. Alternatively, have multiple folders on screen to simply select, copy, and paste from one to another.
5. Enter the target world and deposit the desired items to be duplicated into a chest.
6. Exit the world and return to the main menu; the game should save.
7. Copy and paste the duplicated level.dat files back into the target world folder.
8. Enter the target world. The desired items should be both in the inventory and in the chest.

Extra info: These files also contain your current location and your exp. Theoretically, you can enchant some gear, deposit it in a chest, then load the level.dat file to preserve your level and keep the enchanted gear. Another potential use is to use up your inventory while building then load a backup to keep your progress and refill your inventory with the building material. You could even use this to try multiple times to kill the Ender Dragon or Wither without risking your gear and inventory.

Disclaimer: The environment and mobs are not saved with this method, so do not attempt to summon the Wither near places of importance or important mobs. Instead, back up the entire target world folder and load it in event of failure. Perform test runs to ensure that this method works.

This method is unlikely to be patched because it requires access to the save files and is not an in-game mechanic.

Alt+F4 v2.0 - Task Manager

Alt+F4 is patched, but using Task Manager to end the task, on the other hand, is NOT patched, and still works. This is very similar to the Alt+F4 method. Steps:

1. Open task manager
2. Go into the world you want to dupe the items in
3. Make sure 'Pause on Lost Focus' is off. Do this by pressing F3+P until you see something like "[Debug] Pause on lost focus: disabled" in chat
4. Put the items that you would like to dupe in your inventory
5. Close the world and open it up again
6. When it loads drop the items on ground by pressing opening your inventory and dragging and tossing them out. Don't close your inventory.
7. Quickly press ALT+TAB or CTRL+SHIFT+ESC to get into Task Manager
8. End the task "Java(TM) Platform SE Binary" or "OpenJDK Platform Binary"
9. Open Minecraft and load the world again
10. Collect your items

From testing, it doesn't always work. Try playing with different timings.

Video here:

SP and MP

Explosive fireworks + elytra duplication (MP only)

This section needs expansion.

 

You can help by expanding it.

This duplication glitch works on 1.16.5 multiplayer. It requires an elytra and firework rockets that deal damage to the player. If the rockets do not damage the player, the duplication will not work. Video below: (duplication glitch starts at 0:33)

This is known to work in vanilla servers and realms, however Spigot has patched the bug and Paper has patched it long before its discovery.

Dirt Duplication

The mechanism for growing giant spruce trees is known to be glitched in JE 1.16 snapshot. Instead of growing a giant tree on the saplings, the game grows the tree on the first position where space is sufficient and a dirt block is present in the north-west position. When the tree is grown, all the dirt blocks are filled in. With bone meal and piston automation, a semi-auto dirt duplicator can be produced (YouTube by ilmango).

Lead Duplication (note: does not work in 1.16.4)

Bring an animal to the end, put a lead on it, and then lead it into the end portal. When you get back, it should have dropped two leads. Sometimes one of the leads ends up in the end, so make sure to check there. It may not always be in the end, though. This also works when bringing animals into the nether.

Book player-profile rollback glitch

This duplication glitch works on Singleplayer and Multiplayer. All you have to do is place a chest in front of you and then leave the server as it saves your player data, then relog and put the items you want to dupe from your inventory in the chest, get a book and quill, overload the book with excessive characters and it will cause you to get kicked from the server and rolling back your player data to last save while server files stay the same. As a result, the items will be in both your inventory and the chest.

The book mod (requires fabric download and custom download to work) automates the process.

Video here: https://youtu.be/ml3HkqNfUH4

Piston-based duplication of rails and carpets (Patched on paper)

Carpets can be duplicated using a contraption made of two Slime Blocks, a Sticky Piston, and an Observer. This glitch gives infinite fuel and is very easy to automate give thousands of carpets per hour tutorial: https://www.youtube.com/watch?v=ezM2Hs_-hbE

Bottom Layer

Top Layer

https://www.youtube.com/watch?v=U-9ihB7EmKI and https://www.youtube.com/watch?v=mGQLDJ8dNGs&t=3s are in-depth tutorials that show how to do so

Dragon's Breath Duplication

Whenever the dragon lands on the end portal and releases the purple fog, be above or below the purple fog, look at the fog at a steep angle, and proceed to harvest the dragon's breath. The fog will first shrink as intended, but after it reaches the smallest size, it will expand with each bottle used, and keep expanding until the fog disappears as too much time passed. (YouTube by Underscored Frisk)

Shulker Box breaking glitch

Shulker Box dupe allows you to duplicate any item in Minecraft singleplayer or Realms. This glitch works with 2 players or with an auto mine mod. So you quickly spam your item in and out while it being broken. The key is to take the item out just before the shulker box breaks. This may take a few tries but eventually you will dupe your items.

You can also use autoclicker with these settings: time between clicks- 1sec 487milisecs. Then you bind the autoclicker to key n, and automine to key m and press n,m,right click at the same time. This opens shulker. Hover over item you want to duplicate; shulkerbox should break and item in it, and item on the ground.

Video here https://www.youtube.com/watch?v=6hLxebiG3EA

Piston-based TNT Duplication

TNT duplication works in a similar way as rail duplication. A TNT block is BUD-powered, such that when the contraption is pushed by a piston, the TNT is updated and ignites into a primed TNT entity. Then, the piston moves the TNT from the list of TNT block left. This doesn't so much duplicate the TNT block as it creates free primed TNT entities from it without deleting it. Many TNT duplicators still work, but unless properly constructed will blow themselves up.

One common TNT duplication design uses a minecart on a detector rail to power the slime block it is placed on, and moves a TNT block next to a coral fan underneath, the combination of the TNT and the coral duplicates the TNT whenever the whole contraption is moved forward with a piston. For an indepth tutorial of this one checkout Cheesysponges video https://youtu.be/3Izrj2m6Li4

Slice 1

Slice 2

The second slice may be placed on either side, and the coral fan has been marked with vines. To prime the mechanism, the upper slime blocks must first be moved forward, pushing the TNT under the rail. After this, moving the whole assemblage forward with a piston will duplicate the TNT, spawning a lit TNT entity directly below the TNT block.

For a list of variations, see e.g. [1]. TNT duping as a glitch is notable in that it has been patched by Mojang Studios several times in the past but was ultimately allowed in the vanilla game due to its immense value to the technical community. In the words of Mikael Hedberg, "TNT dupers fill a slot in the game that the intended game mechanics still cannot."

Gravity Block Duplication

There are many ways to do this, but the basic idea is the same.

A gravity-affected block is pushed toward an end portal. It becomes an entity as it falls into the portal, and it travels into the other dimension's "spawn point.", but before it's removed from the original dimension, it bounces off an entity in the portal (in a vehicle so it won't go through), and is caught by some pistons. It then turns into a block and is returned to its original location. This process can be looped using redstone. It works for any block that is affected by gravity, except for primed TNT because it would blow up the contraption and cannot become a block again in any case.

Dragon eggs and anvils fall differently from each other and other gravity-affected blocks such as sand, gravel, and concrete powder. Neither dragon eggs nor anvils work in a sand/gravel/concrete powder duplicator because of this. However, it is possible to create a machine that can duplicate dragon eggs and anvils but not sand/gravel/concrete powder. They both can be duplicated and sent into the End as either falling entities or items.

Tripwire Hook Duplication

Transmitting the update from the passive hook to the active hook by disconnecting the tripwire circuit. If using doors, they must be open when supporting the hooks.

W			E

Transmitting the update through redstone wire in EW direction (direction is only required for triggering duplication).

Tripwire Hooks are duplicatable, but only in certain directions. It may work in some directions, but not others.

Principle and realization

When a tripwire hook is placed to complete a tripwire circuit or updated by tripwire (these updates are only sent to hooks on west or south), it (referred to as the active hook, the opposite hook as the passive hook) first sets the states of the passive hook, and then sets its own states. It is duplicated if a block update from the passive hook makes it drop.

The update can be sent from the passive hook to the active hook through redstone wire. The hook should be placed on a door, so that the redstone wire can break it by activating the door. Another strategy is placing each hook on an activated door or trapdoor, and deactivating the tripwire, so that the passive hook is broken by the door it is placed on, which disconnects the tripwire circuit, immediately breaking the active hook in the same way. These two structures are shown in the schematics.

Classification

This section classifies current tripwire hook duplications according to how the active hook starts its calculation, as placing duplication and triggering duplication, and how the update is sent from the passive hook to the active hook, as redstone wire updating duplication and disconnection updating duplication. Since placing a hook cannot produce a falling edge, there are only 3 classifications, compared in the table below. Rarely, different methods are combined in one duplicator^[2].

Selection

The author suggests considering these points sequentially when selecting a tripwire hook duplicator:

Situations with no choice

• Before 19w13a, the only option is using a dual edge duplicatior.
• Without redstone products, the only option is using a disconnection updating triggering duplicatior. For semi-automatic use, apply the dual-use target line for placing the hook and opening the door.

Possibly better choices for specific versions

• Before 1.20-pre2, dual edge duplication or fast click duplication is often more practical if you have enough materials.
• Before 24w36a, with simultaneous demand for string, a tripwire-duper-triggering redstone-wire-updating triggering duplicator is preferable.
• If it is possible to update up to 24w33a, it is preferable to prepare special tripwire before updating, and build a redstone wire updating triggering duplicator to use after that.

Fast click or not

• If you are obtaining hook for trading in the early game, and have a fast click tool, a redstone wire updating placing duplicatior is probably preferable. It is far more productive than a regular automatic duper, and is likely to meet such demands.

If neither of the situations above holds, then consider a regular automatic duper.

Scale

• For small demands, one or two units can be used. The trigger is selectable, where availability of materials is the primary consideration.
• For large demands, you need to stack multiple units. The horizontal-piston-triggering duper^[3] is alternating tileable^[4] and therefore recommended.

Construction and operation

This section is about the construction of these dupers and, for those that need player operations, how to operate one.

Disconnection updating triggering duplication

Apart from the basic structure including two hooks on doors or trapdoors and one tripwire block, a semi-automatic duper of this type consists of the following two parts:

Selective tripwire trigger

The falling edges required for breaking the passive hook can be generated by selective triggering^[5][6]. An entity elevated by a thin block is commonly used.

Door opener

This part opens the door or trapdoor under the passive hook after duplication, so that you can place another hook on the door and dupe again. A redstone circuit works, but it takes at least 2 clumps of redstone dust^[7], which is unnecessary. A practical alternative solution is to design a target line, where you place a passive hook on the door (or trapdoor) when it is open, and open it when it is closed^[8]. There have been three structures for this purpose:

1. Place the passive hook on the top half of an open door, stand behind the door, and target toward a stairs block horizontally and diagonally through the closed interaction box of the door, on which target point you place the hook^[9].
2. Similar to the previous one, but a trapdoor is used instead of a door, the player stands with their eyes inside the trapdoor when it is closed, and another trapdoor is placed through the body of the player to prevent the player from crawling^[10].
3. Similar to the previous two, using a top trapdoor, but place the targeted stairs above the passive hook, and look through the closed interaction box of the trapdoor^[11].

Redstone wire updating placing duplication

This type requires no additional structure. To dupe, keep the tripwire powered, and simutaneously place hooks quickly (usually with a fast click tool) and hold break to break them. The placed hook can be removed by an additional device^[12], but it is nonessential.

Redstone wire updating triggering duplication

For an automatic duper, all these three parts have variants:

Tripwire circuit

It usually consists of two hooks and a single, regular tripwire block. However, there is a variant, which includes special tripwire and multiple tripwire blocks^[13].

• Some of these dupers still work, but since special tripwire cannot be prepared, they can no longer be constructed.
• The roles of special tripwire include:
  1. Disarmed (and not stuck powered) tripwire disconnecting the tripwire circuit, which is useful in two aspects:
     • Making use of multiple tripwire blocks, by triggering disarmed and armed tripwire alternately, so that the hook is duped for multiple times every period.
     • Keeping the door closed after duplication, so that the products do not fall behind the door and get caught on the block under it. As a result, these dupers, with redstone wired above tripwire (will be mentioned later), are the only ones to support water collection.
  2. Overpowered tripwire (usually also disarmed to keep the tripwire circuit disconnected) preventing products from triggering it.
• The special tripwire can be triggered like regular dupers, but can also be part of a tripwire duper, which is preferred in its applicable versions because, apart from no need for an additional trigger, string is usually wanted to be sold together with the hooks.
  • Hook dupers that trigger such tripwire in a regular way can be constructed below 24w33a, and used in a higher version.
  • Those including a tripwire duper only work in versions where the tripwire duper work.

Door opener

Make sure that the redstone wire updates the door only once. More updates cause the door to pop off the hook on it. There are basically two modes of wiring redstone—wiring under and above the tripwire.

• Their respective characteristics:
  1. Wiring under the tripwire requires less redstone dust, but may obstruct the trigger and the collector.
  2. Wiring above the tripwire requires more redstone dust (usually by 2 clumps), but leaves more room for the trigger and the collector.
• If wiring under the tripwire is not obstructive, choose it. Otherwise, wire above.
• To achieve 1-wide alternating tileability, use these two wiring modes alternately^[14].
  • Another strategy for tileability is using 15-block redstone wire. This makes sense not in a regular duper but in one with special tripwire.

Tripwire trigger

Tripwire can be triggered manually by moving onto and off it or automatically periodically. Below is some information about two frequently used triggering methods.

• Minecart
  • The minecart clock is one of the simplest periodic triggers. It conflicts with wiring redstone under tripwire. There is a trick that uses a single hopper minecart both to trigger the tripwire and to collect products^[15].
• Piston
  • This method uses pistons to allow entities to trigger the tripwire when it is not triggered, and push them away when it is triggered. The signal from the hooks should not be reversed in order to avoid delays. The pistons can be placed in different directions:
    1. Horizontal—Place the piston under the tripwire facing the passive hook, and place an armor stand in front of it^[3]. This is simple but conflicts with wiring redstone under tripwire.
    2. Facing up—Place the piston beside the redstone wire (to be precise, the charged conductor(s) under the active hook(s)), put the entity across the piston head and the active hook(s), and place a block with a certain collision box (such as a lantern for a boat^[16] or chains for a minecart^[17]) to prevent the entity from going away from the tripwire too much. This is a little more complex, and makes use of transverse space, in turn allowing wiring redstone under tripwire.
    3. Facing down—A sticky piston facing down along with honey blocks can be used to simutaneously control multiple entities^[13].

Another issue is that most triggers rely on entity ticking. This disallows duping in lazy chunks, while avoiding its risk of duping out of control.

Video

Bedrock Edition

Sand Duplication (Works 1.20.1+)

This method works by using redstone torches to power large dripleaves with sand blocks placed above them to duplicate sand. It's recommended to build this in either the Nether or the End.

1. Gather at least 2 sand blocks, 1 redstone torch, 1 dirt (or any other block dripleaf can be placed on) and 1 big dripleaf.

2. Build a Nether portal.

3. Secure the portal and either build a shelter or dig as many blocks down respective to the amount of sand you're using to safely house your duplication system.

4. Place the block(s) you're using to plant your dripleaf.

5. Place the redstone torch adjacent to your dripleaf to power it.

6. Place the sand on top of the dripleaf.

7. Leave the Nether.

8. Re-enter the Nether portal.

9. The sand should be duplicated once you re-enter the Nether.

It works for all falling block (Anvil, Gravel,Concrete Powder)

Explanation: https://www.youtube.com/watch?v=noV9JczPFBM

Dirt Chest (works 1.16.1+)

When using this method there might be a chance the items will get deleted, so creating a backup is recommended. This method will not work on Realms.

1. Gather all the items you want to duplicate as well as a chest.

2. Place your chest, and make sure there is 4 dirt in front of the chest.

3. Save & Quit, and then rejoin the World.

4. Place the items you want to duplicate in the chest and quickly break 4 dirt in front of the chest 1 y-level below it in a 2×2 square shape then wait 4 seconds.

5. Quickly forcibly close the application.

6. Rejoin the game. One of three things will have happened;
A) The items will have duplicated (both in inventory and chest),
B) The items will have been removed (neither in inventory nor chest),
C) Nothing will have happened (in chest or inventory).

Explanation/Source: https://www.youtube.com/watch?v=ptGpINSxhaA

Crafting Table Duplication (Works as of 1.21.94)

This method is for realms. It is performed by putting items in a crafting table then forcibly closing or crashing the game.

First, get 65 of the item you wish to duplicate, a crafting table, and 35 of any other item.

Now place down the crafting table and put a stack of the duplication items on to the crafting grid. Leave the other one in your inventory.

Use the 35 other items to fill your inventory (1 in each slot).

Wait approximately 10-15 seconds then open task manager and end the task of Minecraft, crashing the game. On consoles or mobile, use the sytems home button/menu to forcibly close the game.

Reopen the game and rejoin the realm.

There should now be a full stack of the duped item in your inventory, and when you open the crafting GUI, there will be another stack on the crafting grid.

Using simulation distance (Works as of 1.21.93)

This method works by using a hopper or minecart with hopper to drag items from a chest outside of simulation distance.

Method 1

1. Turn on game rule showCoordinates and figure out the exact area of two adjacent chunks. Coordinate X=16x (x is any integer) is the western edge of a chunk, while Z=16z (z is any integer) is the northern edge.
2. At the border between the two chunks, place a switch within one of the two chunk, and activate it.
3. Within the other chunk, place 15 redstone dust into a straight line next to the switch and a redstone repeater at the other end of the line. Now the repeater should be at the edge of the chunk. These will be called as a group below.
4. Make another n-1 groups in the same direction, where n is your current simulation distance. It is recommanded to set simulation distance to 4 temporarily if it isn't already 4.
5. Replace the repeater in the last group with a hopper.
6. Place two chest on the hopper, creating a large chest spanning chunk border. Note that you must place the chest on the hopper before placing the chast located in another chunk. The facing direction of the chest doesn't matter.
7. Place the item you want to duplicate in the LAST slot of the large chest, optimally an unstackable one. If you want to duplicate multiple items at once, you should put them into a bundle or shulker box, then duplicate it.
8. Go back to the chunk the switch is in, and reload the chunk.
   • In singleplayer, log out and log back in.
   • In singleplayer or multiplayer, build a nether portal within that chunk, go to the nether and then go back to overworld. Note that there can't be other players nearby as they cause the chunks to stay loaded.
9. Don't leave the chunk. Deactivate the switch and activate it again.
10. Reload the chunk again with aforementioned methods.
11. Check the hopper and the chest. If duplication succeeded, there should be an item in both of them.
12. If you want to duplicate more, repeat from step 7.

Method 2 (This method does not guarantee 100% success)

1. Do the same as step 1-4 in method 1, but don't activate the switch.
2. In the last group, remove the last redstone dust and the repeater; replace them with a redstone conductor block and powered rail respectively. Place a minecart with hopper on the rail. Note that after duplication the minecart with hopper should be moved back.
3. Behind the powered rail (in another chunk), place another powered rail, a chest above it and a block behind it.
4. Put the item you want to duplicate into the chest, optimally an unstackable one. If you want to duplicate multiple items at once, you should put them into a bundle or shulker box.
5. Go back to the chunk the switch is in, and activate it.
6. Log out and log back in. In multiplayer, make sure that there is no player near the chest.
7. Check the minecart with hopper, and the duplicated item should be in it.

Chunk save stating

This method works by causing the game to crash in a way that only the chunk you are standing in will not save correctly, this will cause the chunk you are standing in to revert to the last save, allowing you to dupe in that chunk.

Explanation of how it works: https://youtu.be/XTkivXhbcMA

Saddle Duplication (Works 1.21.73+)

This method has only been tested in 1.21.73, survival mode.

Saddle a pig, then kill it. Two saddles will drop.

Bundle Duplication Glitch (Works 1.21.82+)

This method works in multiplayer and singleplayer, by taking the objects in the bundle out as it goes from one hopper to another.

1.- Put the items you wish to duplicate in a bundle, and two hoppers facing at each other making a loop.

2.- Put the bundle with the items in one of the hoppers.

3.- Shortly before the bundle goes to the other hopper, right click to get the items out.

4.- If done correctly you should have the items on your inventory and you should also see that the items are still inside of the bundle.

Never try to put the items while the bundle is cycling in the hoppers, as they might disappear.

References

Navigation

v t e Tutorials
Introductory Basics Menu screen Java Edition Bedrock Edition Game terms Playing with a controller Newcomer survival Beginner's guide First ten minutes Second day Third day Best biomes to use Hunger management Things to do Things not to do Simple tips and tricks Survival mode progression Shelters Best biomes for homes Best building materials Building and construction Navigation Shelters Types
General General Achievement guide Advancement guide Minecraft Nether The End Adventure Husbandry Adventuring Best enchantments guide Breaking a fall Breaking bedrock Chunk loader Combat Complete main adventure Creating a village Dual wielding Desert survival End survival Exploring caverns Gathering resources on peaceful difficulty Getting food quickly Getting max gear Headless pistons Hitboxes Horses Indestructible end crystals Managing slimes in superflat mode Mapping Measuring distance Minecraft in education Mining Ancient Debris Diamonds Fossils Nether hub Nether portals Nether survival Organization Pillar jumping Phantom-proofing Spawn-proofing Summoning jockeys Things to do when bored The Void Thunderstorm survival Time-saving tips Transportation methods Units of measure Village mechanics Trading X-ray glitches Zombie siege defense Enchanting and smelting Enchanting mechanics Anvil mechanics Automatic smelting Manual smelting
Challenges General Acquiring a conduit Archaeology Curing a zombie villager Conquering a mountain Defeating a bastion remnant Defeating an End city Defeating a monster room Defeating an ocean monument Defeating a Nether fortress Defeating a pillager outpost Defeating a stronghold Defeating temples Defeating trial chambers Defeating a woodland mansion Defeating a village raid Defeating the Ender dragon Defeating the Wither If it escapes Exploring an ancient city Locating a stronghold Obtaining every music disc Obtaining every block Non-standard survival Adventure mode survival Custom maps Half hearted hardcore Hardcore mode Surviving in a single area indefinitely Infinite desert survival Island survival Manhunt Mob switch Nomadic experience Trapping every mob Skyblock survival Skywars survival Speedrunning Starting in the Nether Starting in the End Superflat survival Java Edition Bedrock Edition Ultra hardcore survival The World Starts With One Getting to the world border Village only survival Challenge maps Beating a challenge map Creating a challenge map
Constructions Constructions Adding beauty to constructions Airlock Architectural terms Building a cruise ship Building a metropolis Building a rollercoaster Building micro shelters Building safe homes Building water features Chunk ban Color palette Creating shapes Defense Elevators Endless circling pool Furniture Glazed terracotta patterns Hiking trail Making nice floors Pixel art Ranches Roof types Curved roofs Roof construction guidelines Roof decorations Secret door Settlement guide Underwater home Walls and buttresses Water gate Water-powered boat transportation Block breaking Blast chamber Igniting TNT underwater Wither cage
Farming Blocks and items Amethyst Armor Azalea Bamboo Basalt Bedrock Blaze Rod Bone Meal Cactus Cat gift Chorus Fruit Clay & Mud Cobblestone Cocoa Beans Copper, Nautilus Shell & Trident Crops (Beetroot, Carrot, Potato, Wheat) Dirt Dragon's breath Dripstone Egg Enchanted Golden Apple Experience Fern Fish Flower Froglight Ghast Tear Glow Berries Glow Ink Sac Glow Lichen Goat Horn Gold Hanging Roots Honey Ice Iron Kelp Lava Meat Moss Mushroom Music Disc Nether growth Nether vine Nether Wart Obsidian Ominous Bottle Powder Snow Pumpkin, Melon Rooted Dirt Sculk Turtle Scute Seagrass Sea Pickle Snow Soul Soil Sugar Cane Sweet Berries Tree Vine Villager trading hall Wither Rose Wool Mobs Mob farming Mob grinding Monster spawner traps Allay Animals Axolotl Bee Blaze Breeze Cat Cave Spider Chicken Creeper Drowned Ender Dragon Enderman Fox Frog Ghast Glow squid Goat Guardian Hoglin Iron golem Magma cube Phantom Piglin bartering Pillager Raid Shulker Skeleton horse Slime Squid Turtle Villager Wandering trader Warden Witch Wither Wither Skeleton Wolf Zombie Zombie villager Zombified piglin
Mechanisms Various devices Redstone Circuits Components Dust Mechanics Tips Automatic respawn anchor recharger Combination locks Command block Crafter Flying machines Hopper TNT Item sorting Item transportation Mechanisms Observer stabilizer Randomizers Redstone music Doorbell Rube Goldberg machine Shulker box storage Detectors Block update detector Comparator update detector Daylight detector Minecarts Train station Minecarts Storage Storage system Traps Snow golems TNT cannons Trapdoor uses Trap design Traps Pistons Piston uses Piston circuits Quasi-Connectivity Zero-ticking Instant repeaters Tripwire Tripwire techniques Advanced redstone Advanced redstone circuits Arithmetic logic Calculator Command stats Hourly clock Morse code Printer Redstone computers Redstone telegraph
Multiplayer General Griefing prevention Hiding chests Multiplayer Survival Spawn jail Playing on servers PvP Bases Joining a LAN world with alternate accounts Server setup Setting up a Java Edition server Forge server Hamachi server Setting up a Bedrock Edition server Server maintenance Setting up a LAN world Server startup script FreeBSD OpenBSD Ubuntu Ramdisk enabled server
Technical General Creating Forge mods Moving structures using structure blocks from world to world Improving frame rate Minecraft help FAQ Note Block Studio Programs and editors Running the data generator Update Java See Minecraft's code Downgrading Restoring a hardcore world Maps Custom maps Map downloads Command NBT tags Falling blocks Updating old terrain using MCEdit Resource packs Creating a resource pack Loading a resource pack Models Sound directory Data packs Adding a new dimension Adding custom enchantments Adding custom paintings Adding custom trims Creating a data pack Custom structures Installing a data pack Repairing a world corrupted by a data pack Creating Minecraft media Creating videos Livestreaming Hide Server IP Game installation Installing snapshots Installing Minecraft Preview and beta versions How to get a crash report Installing Forge mods Custom Minecraft directory Playing and saving Minecraft on a thumb drive Playing and saving Minecraft on a thumb drive with the old launcher Recover corrupted saved world data Run Minecraft through Google Drive Save game data to Dropbox (world data only) Saved data Dropbox guide Create a Mac OS X startup daemon Playing Java Edition on ChromeOS
Outdated Farming Potion farming End of light mob farms Door-based iron golem farming Villages Legacy Console village mechanics Pre-1.14 village mechanics Village chaining Glitches Duplication Far Lands Contraptions Minecart booster Repeater reboot system Instant wire Water ladder Water tram Challenges Survival with no enabled data packs Construction Man-made lake Other Custom texture packs How to get a crash report (old) Installing mods Setting up a Spigot server Update LWJGL Update Minecraft Custom world generation