Trial Chambers structure in Minecraft

Where Trial Chambers generate

The game places at most one Trial Chamber in each 34 × 34 chunk region of the Overworld (544 × 544 blocks), never closer than 12 chunks to the next one, so one is rarely far away. They start deep, between Y -40 and Y -20, and most rooms sit a little higher: caves around Y -20 to 0 often cut into their walls. You will usually find one by accident while caving or mining, when the walls suddenly turn to polished tuff and copper bulbs. Every Overworld biome can host one except the Deep Dark.

Get a map or the coordinates

• Cartographer: a Journeyman (level 3) Cartographer villager can sell a Buried Trial Chambers Map for 12 Emeralds and a Compass. Each cartographer gets only 2 of its 3 possible level 3 trades, so you may have to check several.
• Abandoned Camps: the hidden chest of an Abandoned Camp always holds one explorer map, and 1 in 7 of them is a Buried Trial Chambers Map.
• Command or seed map: with cheats on, the /locate command shown above prints the coordinates. With cheats off, the seed map gives the same answer.

Once you know the coordinates, dig a staircase down rather than a straight shaft: the chambers are large and you may land in the middle of a fight.

How a trial works

Each room is guarded by a trial spawner. It wakes up when a player is within 14 blocks and in its line of sight, then spawns a set number of mobs, more for each extra player nearby. Light does not stop it, so torches will not help, and it stays idle on Peaceful. Once the wave is cleared, the spawner ejects a reward for each player, then rests for 30 minutes before it can be fought again.

Half the time the reward is a Trial Key for every player. Otherwise each player gets food (Bread, Cooked Chicken or a Baked Potato) or a Potion of Regeneration or Swiftness.

The mobs depend on the spawner and on the chamber. Close-range spawners pick from zombies, husks and spiders. Small fast mobs come as baby zombies, cave spiders, silverfish or slimes. Ranged spawners use skeletons, strays or the poisonous Bogged. The Breeze is the chamber's own mob: it jumps around, deflects arrows and fires wind charges that knock you back. It drops 1 or 2 Breeze Rods: keep one for the Mace.

Vaults and keys

A vault opens with one Trial Key. Each player can unlock each vault once, so in multiplayer every player gets their own reward from the same vault. A vault remembers up to 128 players, and it never resets.

One opening gives 1 to 3 common items, has an 80% chance of a rare item (otherwise one more common item) and a 25% chance of a unique item. The best odds per opening, from the 26.3 loot tables:

• Diamonds (1 to 2): 8.5%
• Golden Apple: 8.3%
• Smithing Template (Bolt Armor Trim): 6.3%
• Enchanted Diamond Chestplate or Diamond Axe: 3.5% each
• Trident: 2.1%

The rest is emeralds, wind charges, arrows, other enchanted gear and books, the Guster banner pattern and the Precipice music disc. The entrance corridors also hide chests that can contain a free Trial Key, so search them before the first fight.

Start an ominous trial

For harder fights and better loot, drink an Ominous Bottle to get Bad Omen, and stay away from villages, where it starts a raid instead. When a trial spawner sees you, Bad Omen turns into Trial Omen for 15 minutes per level of Bad Omen (75 minutes at level V), and every trial spawner within 15 blocks that sees you switches to its ominous version.

Ominous spawners send mobs in enchanted armor with better weapons, and every 8 seconds they drop items above you: lingering potions (Wind Charging, Oozing, Weaving, Infestation, Strength, Swiftness or Slow Falling) plus arrows, fire charges or wind charges. A cleared ominous spawner gives an Ominous Trial Key 30% of the time. Drink a Milk Bucket to remove Trial Omen if you want to stop.

Ominous Bottles drop from Pillager captains killed outside a raid, and about 1 vault opening in 6 gives one, so a first normal run funds your ominous runs.

Ominous vaults and the Heavy Core

Ominous vaults sit on small altars with red candles and only accept an Ominous Trial Key. One opening gives 1 to 3 common items, has an 80% chance of a rare item and a 75% chance of a unique item. Odds per opening:

The Heavy Core goes directly above a Breeze Rod in a crafting grid to make the Mace. At 7.5%, one Heavy Core takes about 13 ominous vault openings on average, and each player opens each vault only once, so plan on clearing more than one Trial Chamber. The same vaults also give the Flow banner pattern, the Creator music disc, blocks of emerald or iron, and books with the mace enchantments Density and Breach. These odds are for Java Edition; Bedrock Edition gives the rare roll far less often.

Tips to survive and loot efficiently

• Bring a shield and a melee weapon. Breezes deflect most projectiles, so a bow alone will not do.
• Clear one room at a time. Spawners only wake up when you are close; stepping back keeps you from triggering two at once.
• Keep your Ominous Bottles. Drink one only in a chamber you have already cleared once: you know the rooms, and ominous waves hit harder.
• Mark your way. Corridors look alike and branch often; a line of torches or blocks saves a lot of time on the way out.
• Come back later. Trial spawners reactivate after 30 minutes, so a chamber near your base becomes a renewable source of keys.

✓ Checked in Java Edition 26.3 · updated 31 October 2026