Door

Doors are blocks that are only obtainable through crafting. Doors come in two varieties: wooden doors made from planks, and iron doors made from iron ingots. Doors are hinged at a corner and have two states: rotated clockwise and rotated counter-clockwise.

Destroying the block beneath a door will break it. Swords are also effective against wooden doors, though the sword will still take double damage.

The sound of opening and closing of a door can be heard up to 16 blocks away.

Wood Doors
Upon clicking a Wood Door with either the left or right mouse button the block will shift from one state to another state allowing or preventing passage. These may also be opened by using Levers, Stone Buttons or Pressure Plates.

Iron Doors
An Iron Door is only able to be toggled by a switching mechanism such as a Levers, Pressure Plates or a Stone Button. If an iron door has at least one "open" signal connected then it will be "open". However, a clever engineer can make it so that the door blocks passage when "open" and allows it when "closed". This creates the possibility to make doors that are only controllable from remote locations using a switch and Redstone; otherwise just putting a redstone torch in front of the door opens it.

Iron doors can take quite a bit of time to destroy even with a pickaxe. To destroy them quicker, simply break the block beneath the door. Builders can discourage this by placing a lava block at the top of a 1x1 shaft above the door, and/or by placing the door on top of an obsidian block

Double Door
If two doors are placed adjacent to each other, they will orient with their handles inward, creating a double door. The left half of the double door will be in the rotated clockwise state while the right half of the double door will be in the rotated counter-clockwise state. It is possible to make a double door with pressure plates like soand so. Boats can now pass through double doors, with the doors acting as locks on canals or docks.

Looking at closed, double doors, it seems like the first door is mirrored to create the second, but this is not actually the case. The second door is rotated 90 degrees from the first one, and it is placed in the open position. This is why opening/closing both doors simultaneously using a redstone mechanism yields unexpected results. If one door is "on" (receiving power), the other door must be "off" in order for both doors to be open/closed.

Draw Bridge
An interesting property of a door is that you can walk on top of them. An easy way to make a drawbridge is to use two doors, two switches, and at least a 2 by 2 by 2 deep pit. Have the two doors on opposite sides at the bottom of the pit so that when opened the doors create a small line in the middle. Put the switches on the same sides of the door so that when pushed both doors will open; you should have just enough time to get across.

Mob Trap
This 3x3x3 reusable mob trap can be made using only 4 doors, 1 pressure plate, and 1 block of anything. The first thing you want to do is stand on the centre of where you want your trap to be. Then place the doors making sure they are reversed on the 4 blocks that are in front, behind, left, and right of you. When that is done exit the trap by opening one of the doors and place a pressure plate in the centre of the mob trap. If all the doors open as soon as you put the pressure plate all the doors should open at once. Finally, to keep mobs from exiting place the 1 block on the top of the trap to keep them from jumping off the pressure plate and opening the doors. I recommend using wood doors for catching mobs because if you trap yourself you can easily get back out. To kill the mob inside simply walk up to one of the doors and hit the mob with something.

This trap can also be made into a re-loadable land mine trap. Just dig a 2 blocks into the middle and fill the bottom with water. Then put a tnt block on top and the pressure plate on top of that.

Mobs also can not see players through closed doors. If you stand on the inside edge of a door, you can attack through doors. The mobs may walk torwards you, but will not attack unless you open the door. Likewise, if the mob is on the inside edge, they may attack you through the door. This can be utilized to make a safe area while killing off mobs in a pit. Make a deep pit, 1-3 blocks wide. When a mob falls in, you can attack through the door. Once you deal damage, they will walk closer, making it even easier to kill. The mobs can not hurt you, but you can hurt them. Even creepers won't explode. Spiders can see you through the doors, but can not damage you. Be careful, if you accedentally open a door, the mobs will all rush torwards you, ready to attack.

Door Farming
Placing a door next to a block of sand with a cactus on top of it will cause the door to break and drop two doors. This tactic may be useful for making doors if you are low on either wooden planks or iron or you want more than just a few doors. This is a glitch, and will most likely be eventually fixed.

Features

 * Because the door occupies the edge of a tile, if you stand in the center of the tile you can hit things on the other side. Make sure you place the door from the outside of your house so that you can attack mobs on the other side, but they cannot attack you. As long as you follow this rule and make sure the door is on the edge that will be exposed to danger, monsters cannot harm you from the outside, but you can fight them without opening the door.
 * The above method also works for arrows: those shot from the inside and from a certain distance won't collide with the door (unless they hit the point were the two halves of the door connect), but go straight through without losing speed. Those shot from the outside will still collide and get stuck on the door. This glitch is highly dependent on the distance between the player and the door: to be able to go through, arrows must be fired from 7, 10, 11 or 14 blocks away to be able to go through.
 * Minecarts will not move through doors. Water will not pass through either, useful for flood control. Another practical use of the door's water glitch is to leave a door open as an entrance to something underwater that is water-free on the other side.
 * Although minecarts cannot pass through doors horizontally, they can drop through doors if the door is in the right state (open/closed). This is an effective way to control minecarts.
 * Doors placed on doors will be lost, and nothing will happen.
 * There is another glitch that can only be made by using a map editor or cacti. If the lower half of a door is copied, it is possible to get a 1 block high door.
 * If you stand in an open door, then close it, you don't collide until you walk out and back in.
 * It is impossible to place doors on an ice block or glass block.
 * In SMP if you put 2 half doors (not on opposite sides) on the sides of a block, putting a door in between the doors will cause all 3 doors to break.
 * Sometimes, when you put a pressure plate behind a door, the door will incorrectly open and close when the plate is stepped on (i.e. door closing when plate is stepped on). This is because right-handed doors will rotate counterclockwise when powered, same as left-handed doors. Try placing the door on a different block until you get a left-handed door. (See notes above on double doors.)
 * In SMP, pressure plate lag may cause the server to drag you back behind a closed door when you thought you had already exited. To avoid this, stand next to the door and click it to open, without using the pressure plate.

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