Java Edition:Understacked Items
Understacked items are items with a count of either zero or negative, below the regular minimum of 1. All items as understacked items are obtainable continuously from Indev 0.31 20100124 through 15w40b (1.9 snapshot) using the TNT + Chest Method. Several methods work after this version range as well. All understacked item stacks are deleted when updating to 16w32a (1.11 snapshot) or later, meaning 1.10.2 is the last version understacked items can be kept in.
Understacked items allow for the creation of overstacked items by underflowing the count below -128 and also allow for item duplication.
Obtaining
TNT + Chest Method
From Indev 0.31 20100124-2310 to 15w40b (1.9 Snapshot), the player could obtain understacked items by blowing up a chest while taking the items out of the chest.
The first method works from Indev 0.31 20100124-2310 to Alpha v1.2.6 and can be accomplished by blowing up a chest while inside the chests inventory, once the chest has been blown up the chest menu remains open. The items inside the chest menu can be removed and they become zero stack items.
The second method works from Beta 1.0 to 15w40b and is accomplished by pulling the items out of the chest after it is blown up but before the chest GUI disappears, which gives the player a 1 tick window before it is blown up. This is stated to be a 1 tick window (about 0.05 seconds or 50 milliseconds) to grab the items from the chest before the GUI disappears.
The real items from the first variant (left on the ground after the chest is blown up) will cause the held understacked items to revert back to normal if they are picked up. From 15w38b (1.9 Snapshot) and onwards, if this method is attempted it will only result in a 0 Stacked Item and must be in the players hotbar or offhand inventory slots. This is due to understacked items no-longer being able to be moved within the inventory, and prior to 14w33a (1.8 Snapshot) the item stack will display as if the item was single item instead of 0 or negative number.
This method also creates an item duplication method, these understacked items can be picked up while inside an inventory and when right clicked outside the inventory true items will be dropped and the understacked items will still be held by the mouse.
Signs on Non-opaque Blocks Method
In Infdev 20100607 you could obtain 0 item count signs by placing 2 signs adjacent to each other on top any of the following blocks glass, leaves, torches, smooth stone slabs, flowers, and mushrooms. When performed correctly the game will crash and after reloading the world the player will have a 0 stack of signs.
Close Inventory Method
In Alpha v1.0.17_02, there was a glitch where if you had a stack in your cursor and then closed your inventory, the stack would drop, but when you opened your inventory again, the stack would still be hovering in your inventory. This stack dropped on the ground is a zero stack. This will only occur in Singleplayer.
Damaged Equipment Method
In Beta 1.6 and Beta 1.6.1 (not in Beta 1.6 Test Build 3), simply dropping any equipment that was damaged creates a 0 item count. This item can picked up any number of times and fills up the player's inventory quickly. This method only works on tools, armor, and weapons that have durability. Beta 1.6.2 was released solely to fix this bug.
Furnace State Change Method
From Beta 1.6 Test Build 3 to Beta 1.6.2, furnaces can be used to obtain a zero stack of any item. When a furnace changes from unlit to lit or vice versa, the items inside will drop out of the furnace as if it were broken. However, inside the furnace the items in every slot will become zero stacks. To use this on an item that cannot be cooked, start cooking an item and then put the desired item in before the furnace's fire runs out.
Portal Crafting Table Method
From Beta 1.6 Test Build 3 to 12w04a, singleplayer allowed one to create zero stacks. One must do is construct a nether portal, have a method of pushing the player into the portal without player interaction (a delayed piston or water stream works well), and a crafting table in reach. Jump into your player pusher of choice, and before reaching the portal, place the items you wish to zero stack into the 3x3 crafting grid. Once the player reaches the portal, the item will drop twice, once as the full stack that was placed into the table, and the second as a zero stack.
Drop Method
This method works on Beta 1.0 to Beta 1.0_01 servers (multiplayer only), these servers have the PVN 7 which allows any client from Beta 1.0 to Beta 1.1_01 to connect to them. The method occurs randomly whenever the player throws an item, sometimes the item will be a zero stack. The quickest method to get to this zero stack is to looks straight down and spam the drop button (Q by default) until you pick up the zero stack. The zero stack will then act as a 256 stack since when it reaches -128, it will go back up to 127.
Crafting Table Quit Method
In Beta 1.8 Pre-release (both uploads), quitting out of the crafting table while there is an item stack inside of crafting GUI will drop that item stack along with a zero stack of that item. This simple method can be used on any item. This method does not work in multiplayer.
Hopper
This method works in 13w01b. Throwing a stack of items onto 2 hoppers will fill them all up. After picking up the stack that was thrown one of the 64 stacks in hoppers will be replaced with zero stack.
Broken Furnace Inventory Method
In the 1.8 snapshot 14w34a, the furnace did not properly handle items placed within[1], resulting in either their deletion or transformation to zero stacks. The easiest method to obtain a zero stack can be achieved by placing an item into the top furnace slot, and picking it back up into the player's inventory. Upon closing the furnace GUI, the client will be updated on the stack's actual size.
Book Copying Method
From 1.8.1-pre4 to 16w02a (1.9 snapshot), book copying had a bug[2] that could modify the count of the book being copied. This can result to the creation of zero stacks and duplication in a variety of ways. The easiest[test] way to achieve a zero stack is to place a stack of two written books and two book and quills into a crafting grid, which will result in the written books being stacked to zero.
Breaking Bow Method
From 15w31a to 15w36d (1.9 snapshots), shooting from a bow that has 0 durability causes the bow to become a 0 stack. This method was patched for the main hand in 15w37a[3], but with the addition of the ability to shoot the bow from the offhand in this version, it can instead be done in the offhand to create a 0 stack. The offhand method was only fixed in 16w32a (1.11 snapshot) when negative items were deleted.[4]
Thorns Method
From 12w50a (1.4.6 snapshot) when thorns was added until 1.10.2, armor with thorns could become a zero stack when attacked by a mob or player. Thorns armor takes additional damage when it does damage to an attacking mob or player. If this additional thorns damage breaks the armor, then the armor will become a zero stack. The armor will not become a zero stack if it is at zero durability and then the player is hit since this breaks from regular armor damage instead of thorns armor damage. This method works on any armor available at the time enchanted with thorns.
Off Hand Entity Usage Method
From 15w31a to 15w32c (1.9 snapshots), using some 1 stack items on an entity from the player's offhand will make it a 0 stack.[5] The following items can be made 0 stacks with this method:
- Lead on any leadable mob
- Spawn eggs on their respective mob
- Wheat seeds, pumpkin seeds, melon seeds, and beetroot seeds feeding chickens
- Carrots, potatoes, and beetroots feeding pigs
- Wheat feeding sheep or cows
- Bones taming wolves
- Raw porkchop, cooked porkchop, raw beef, steak, raw chicken, cooked chicken, rotten flesh, raw rabbit, cooked rabbit, raw mutton, and cooked mutton feeding wolves
- Raw fish, raw salmon, clownfish, and pufferfish feeding ocelot
- Apple, golden apple, enchanted golden apple, sugar, wheat, and hay bale feeding baby horse (player will mount adult horses instead)
Map Zoom Method
From 15w44a to 15w44b (1.9 snapshots), after crafting together a filled map and shears, the shears item will remain in the crafting table but become a zero stack. The method exclusively allows for understacked shears and the understacked shears will always have at least one damage since the crafting recipe also uses one durability on the shears. In 15w45a, the map zooming with shears recipe was removed which fixed this method.
Item Frame Method
In 15w49a, placing a single item into an item frame leaves a 0 count item in the player's hotbar.[6] This method works for all items at the time and so is the only way to obtain zero stacks of two items added after the TNT + Chest method was fixed: the elytra and end crystal.
15w49a is an unstable version that will crash when an item stack is depleted, such as if a stack of one block is placed. To put down the item frame in this version, ensure you have a stack of at least 2.
Downgrading
In 24w09a (1.20.5 snapshot), the item format was changed from NBT to Components, meaning that any item downgraded before 24w09a will not be recognized by the game, therefore being deleted. By downgrading any item[7] from 24w09a through 1.21.4 (present), down to 14w03a[test]
Behavior
Methods of Subtraction
Right-clicking an understacked item into any inventory will decrease its count by 1. This method works from Indev 0.31 20100128 to 1.6[test], and attempting it past 1.6[test] with a zero stack will result in the item's deletion. Negative stacks <= -1 will not be deleted, but will not produce a separate item and will not decrease in size. This would become impossible in 15w38b, as picking up understacked items with the cursor deletes them.
Right-clicking an understacked item to the side of the inventory screen will decrease its count by 1. Attempting it in 1.5[test] will result in no items being dropped despite decreasing the stack size, but items dropping are restored in 1.6[test]. This would become impossible in 15w38b, as picking up understacked items with the cursor deletes them.
Dispensers and droppers could drop or insert zero or negative stacks, and doing so would decrease their count by 1, from their respective introductions until 1.8.3. In 1.8.4, a private issue was fixed, resulting in dispensers or droppers that tried to drop or insert zero or negative stacks deleting the remaining understacked stack after dropping or inserting 1 item.[8]
Stack Underflow
If the item count goes under -128, it can underflow and become a overstacked item upon saving to disk. To determine the exact number that will be produced from the cast of integer to byte is to divide the integer count by 256, and take the remainder. If the remainder is between -1 and -127, the resulting stack will be negative, if between -128 and -255, the stack will be positive, and if the remainder is 0, then the resulting stack will be a zero stack.
Understacked Item Entities
Understacked item entities have some strange behavior. When the player enters the pickup range of an underflowed item, if the stack is negative, the stack will be picked up, but the item entity will not be destroyed. Instead, the item entity remains as a zero stack, which can also be picked up. To pick up a zero stacked item from an item entity, one cannot have any other of the item on the ground in their inventory, if it is stackable. For unstackables, the item will be picked up every tick until the player is out of inventory space.
Hoppers do not interact with understacked item entities.
Moving the Item Stack
Understacked items could be moved freely in the inventory in nearly any way in the past, except for a few specific exceptions. Past 1.4.7[test], attempting to drop a zero stack to the side of the inventory screen will delete it. In some 1.5 versions[test], attempting to drop items from a negative stack or the negative stack itself to the side of the inventory screen will delete any dropped items. Past 1.6[test], trying to drop a single item off of a zero stack with right click into a slot will result in its deletion.
Understacked items cannot be moved with shift-click in any version.
After 15w38b, understacked items can only be moved with the number keys into the player's hotbar. Attempting to move them out of the hotbar, or in any other way, results in their deletion.
Uses
Duplication
When putting zero-stack items into dropper or dispenser and powering it, the dropper/dispenser will drop unlimited amount of that item.
Overstacked Items
Gallery
Understacked items in a player's inventory
