Trapdoor

The trapdoor is a block item implemented in the beta 1.6 update.^[1]

They are intended to be placed over a single-block hole^[2] (but can be placed over a solid block as well) with a solid block directly adjacent. When activated, they will then open by flipping upwards^[3] toward the adjacent block. If that block is destroyed, the trapdoor is as well. Just like doors, trapdoors can be activated by redstone circuitry. When placed outside, rainfall, water and snowfall do not pass through a trapdoor^[4], but light is let in through the four gaps on its surface.

Crafting

When crafted with six wooden planks, two trapdoors are created. Video

Ingredients	Input » Output	Notes
Wooden Plank	Template:Grid/Crafting Table	Two trapdoors are created.

Trapdoor screenshot 1 — An example of an open trapdoor, shown with its back to a block.

Uses

Redstone

As with doors, trapdoors can be controlled with Redstone circuitry. A charge will cause the trapdoor to change its state, from either on or off, depending on it starting state.

Drawbridge

If you place the trapdoors in a trench in this fashion:

You can create a fairly good drawbridge. You can extend it lengthways, but not widthways. However, it's possible to walk on the ledge of an opened trapdoor if there is enough space above it.

Underground Entrance

Mineentrance — An example of advanced entrance to mine. It is controlled by Redstone underground(Redstone Dust, Torches, Repeaters).

Bugs

Trapdoors seem to break faster using a pickaxe instead of an axe, like wooden slabs.

Trivia

Much like the Piston is based on a mod developed by Hippoplatimus, the hatch is very likely based on a mod from DJoslin. (http://www.djoslin.info/trapdoor.php)
Trapdoors may not be placed next to double half blocks.
Sand and Gravel, if dropped onto a trapdoor will break into items (similar to how sand or gravel falling on a torch will do the same).
Liquids (water and lava) cannot fall through a single hole trapdoor. The trapdoor counts as a block and can't have something else in it, even in it's open state. Trapdoors will stop the block above it whether it's open or closed.

References

Natural
Soil	Clay Dirt Coarse Rooted Dirt Path Grass Block Gravel Suspicious Mud Mycelium Nylium Podzol Sand Red Suspicious Soul Sand Soul Soil
Stone	Andesite Basalt Bedrock Blackstone Calcite Deepslate Diorite Pointed Dripstone Block End Stone Glowstone Granite Infested Block Magma Block Netherrack Obsidian Crying Sandstone Red Stone Terracotta Tuff
Ore/Mineral	Amethyst Bud Cluster Ancient Debris Budding Amethyst Coal Ore Deepslate Copper Ore Deepslate Diamond Ore Deepslate Emerald Ore Deepslate Gilded Blackstone Gold Ore Deepslate Nether Iron Ore Deepslate Lapis Lazuli Ore Deepslate Nether Quartz Ore Redstone Ore Deepslate
Liquid/Related	Bubble Column Ice Blue Packed Lava Flowing Snow Powder Block Water Flowing
Non-physical	Air Cave‌^{[JE only]} Void‌^{[JE only]} Fire Soul

Biota
Wood/Hypha	Logs Stripped Wood Stripped Stems Stripped Hyphae Stripped
Plant	Azalea Flowering Bamboo Shoot Block Stripped Beetroots Big Dripleaf Small Stem Cactus Carrots Cave Vines Plant Chorus Plant Flower Cocoa Dead Bush Fern Large Flowers Tall Torchflower Crop Grass Tall Hanging Roots Leaves Lily Pad Mangrove Roots Muddy Melon Attached Stem Stem Moss Block Carpet Pink Petals Pitcher Plant Crop Potatoes Pumpkin Attached Stem Carved Stem Saplings Seagrass Tall Spore Blossom Sugar Cane Sweet Berry Bush Vines Wheat Hay Bale
Fungus	Fungi Glow Lichen Mushrooms Blocks Stem Nether Sprouts Nether Wart Nether Wart Block Warped Roots Shroomlight Twisting Vines Plant Weeping Vines Plant
Algae	Kelp Dried Block Plant
Fauna	Coral Dead Coral Blocks Dead Coral Fans Dead Sea Pickle
Fauna/Related	Bee Nest Bone Block Cobweb Dragon Egg Frogspawn Sniffer Egg Turtle Egg
Sculk	Sculk Sculk Catalyst Sculk Sensor Calibrated Sculk Shrieker Sculk Vein

Building
Lighting	Candle End Rod Froglight Jack o'Lantern Lantern Soul Sea Lantern Torch Soul
Ornamental	Bamboo Mosaic Bookshelf Carpets Chain Decorated Pot Fences Iron Bars Glass Pane Tinted Stained Glass Pane Glazed Terracotta Honeycomb Block Slabs Stairs Walls Wool
Mineral Block	Block of Amethyst Block of Coal Block of Copper Cut Raw Block of Diamond Block of Emerald Block of Gold Raw Block of Iron Raw Block of Lapis Lazuli Block of Netherite Block of Quartz Bricks Chiseled Pillar Smooth Block of Redstone
Structural	Bricks Cobblestone Mossy Deepslate Concrete Powder Cut Sandstone Chiseled Smooth Cut Red Sandstone Chiseled Smooth Deepslate Bricks Cracked Deepslate Tiles Cracked End Stone Bricks Nether Bricks Chiseled Cracked Red Packed Mud Mud Bricks Planks Polished Andesite Polished Basalt Smooth Basalt Polished Blackstone Chiseled Polished Blackstone Bricks Cracked Polished Diorite Polished Granite Polished Deepslate Chiseled Prismarine Bricks Dark Purpur Block Pillar Reinforced Deepslate Smooth Stone Stone Bricks Chiseled Cracked Mossy
BE & edu only	Elements Hardened Glass Pane Hardened Stained Glass Pane

Utility
Interactable	Anvil Chipped Damaged Barrel Beacon Brewing Stand Cartography Table Chest Ender Chiseled Bookshelf Crafting Table Enchanting Table Fletching Table Furnace Blast Smoker Grindstone Lectern Loom Shulker Box Sign Hanging Smithing Table Stonecutter
Utilizable	Banners Beehive Beds Bell Cake with Candle Campfire Soul Cauldron Lava Powder Snow Water Composter Conduit End Gateway End Portal End Portal Frame Farmland Flower Pot Frosted Ice Heads Item Frame Glow Jukebox Ladder Lodestone Monster Spawner Nether Portal Respawn Anchor Scaffolding Sponge Wet TNT
Redstone/Mechanical	Button Daylight Detector Dispenser Dropper Doors Trapdoors Fence Gates Honey Block Hopper Lever Lightning Rod Note Block Observer Piston Sticky Head Moving Pressure Plates Rail Activator Detector Powered Redstone Wire Comparator Repeater Lamp Torch Slime Block Target Trapped Chest Tripwire Hook Tripwire
Education Edition only	Border Chalkboard
BE & edu only	Allow Compound Creator Colored Torches Deny Element Constructor Heat Block Lab Table Material Reducer Underwater TNT Underwater Torch

Creative only
All editions	Monster Spawner Player Head
Java Edition only	Barrier Command Block Chain Repeating Jigsaw Block Light Structure Block Void
BE & edu only	Allow Compound Creator Deny Element Constructor Lab Table Material Reducer
Minecraft Education only	Border Chalkboard

Commands only
All editions	Petrified Oak Slab Unstable TNT
Java Edition only	Custom Player Head
BE & edu only	Barrier Broken Anvil Chiseled Purpur Command Block Chain Repeating Fern Fern Jigsaw Block Light Block Structure Block Air Void Smooth Stone Bricks tile.purpur_block.smooth.name Unknown
China Edition only	mod_ore

Unimplemented
All editions	Branches Copper Button Colored Wood Planks Coral Slab Dirt Slab Empty Barrel Fish Barrel Furniture Paeonia Sculk Jaw Spike Block Wax Block

Unused
Bedrock Edition only	Bell Stand tile.client_request_placeholder_block.name Glowing Obsidian Invisible Bedrock Nether Reactor Core Smokeless Campfire info_update info_update2 reserved6 Stonecutter (old)

Joke features
Java Edition only	An Ant Block of Coal Box of Infinite Books Torch (Burnt-out) Cheese Copper Sink Copper Spleaves Cursor Etho Slab Funky Portal How did we get here? Leftover Other Portal Packed Air Pickaxe Block Place Block Swaggiest stairs ever Tinted Glass USB Charger Block

Removed

Java Edition only

Bedrock Edition only

MinecraftEdu only

Legacy Console Edition only

Ring Block

Extreme metadata variants
All editions	Seamless Stone Slab Six-sided Hay Bale Weird Piston
Java Edition only	Faceless Jack o'Lantern Overripe Melon Stem Attached Overripe Pumpkin Stem Attached Overgrown Cocoa Overeaten Cake Potted non-flower block Green Shrub Potted
Bedrock Edition only	Diorite Bell Granite Bell Polished Six-sided Bone Block grass_carried leaves_carried Six-sided Purpur Pillar Six-sided Quartz Pillar