Nether Fortresses and Bastions

One grid, two structures

Since 1.16 Java places fortresses and bastions on a shared grid of 27×27 chunk regions with a 4-chunk separation. Each region gets one attempt, and a random roll decides which of the two it becomes: bastions win about two rolls in three, fortresses one. Then the biome check applies: bastions never generate in basalt deltas, and that is the only biome rule either structure has. So in most of the Nether you are never more than a few hundred blocks from one or the other.

Bedrock uses the same 30-chunk shared grid with its own random generator, and the split is the same four bastions to two fortresses out of six. The fortress finder is Exact on both editions; the bastion finder is Exact on Java and Approximate on Bedrock, where about nine in ten markers were confirmed in-game.

Coordinates on both finders are Nether coordinates. Multiply by eight to find the Overworld point above, or divide an Overworld position by eight to see what is near your portal.

What is near a spawn portal on the test seeds

Every seed has both within 400 Nether blocks of spawn, which is the grid at work. A speedrunner cares about the exact figures; a survival player mostly wants to know which direction to tunnel, and the Nearest list gives that from any portal position you type.

Fortresses: blazes, skulls and nether wart

A fortress is a lattice of nether brick bridges and corridors over the lava sea. The bridges hold blaze spawners on open platforms, and blazes drop blaze rods, which you need for brewing stands, blaze powder for Eyes of Ender and fuel for brewing. The corridors spawn wither skeletons, whose skulls summon the Wither, and the stairwells hold nether wart planted in soul sand, the base ingredient for most potions. Chests in the corridors can contain diamonds, obsidian, saddles, horse armour and flint and steel.

Wither skeletons and blazes only spawn inside the fortress's bounding box, so farms are built inside it: a blaze farm around a spawner with a kill chamber, or a wither skeleton farm on a long bridge section with the other spawning spaces removed. Bring fire resistance, a bow for blazes and a slab to crouch under while fighting skeletons.

Bastions: four types and how to raid them

• Treasure room: a tall chamber with a magma cube spawner over a pool of lava and gold blocks, with chests at the bottom. The best loot and the surest source of the netherite upgrade smithing template.
• Hoglin stables: stacked stalls of hoglins, piglins and chests. Lots of loot, lots of mobs.
• Housing units: a tower of rooms and bridges, easy to enter but full of piglin brutes.
• Bridge: a long structure with a gold-block statue, chests along it and brutes on guard.

Piglins ignore you if you wear at least one piece of gold armour, and they barter: throw a gold ingot and they drop ender pearls, fire resistance potions, obsidian, string and more. Piglin brutes attack regardless of gold, hit hard and never barter; deal with them first, from above if you can. Mining gold blocks or opening chests near piglins angers every piglin in sight, so loot quietly or clear the area.

The netherite upgrade template is required to turn diamond gear into netherite, and bastion chests are its only natural source. Ancient debris, the other half of the recipe, generates deep in the Nether at Y 8 to 24; the ancient debris finder shows every block of it for Java seeds, so a bastion trip and a debris mine can share one tunnel.

Looting a Piglin Bastion Remnant! ▫ Minecraft Survival Guide S3 ▫ Tutorial Let's Play [Ep.32]36 min

Planning the trip from your portal

1. Note your Overworld portal's coordinates and divide by eight, or let the portal calculator do it.
2. Open the fortress and bastion finders on your seed, set Nearest to that Nether position and read the distances and directions.
3. Tunnel at Y 30 to 60 toward the fortress first for blaze rods and nether wart; fortresses are safer than bastions for a first visit.
4. Carry a gold helmet, a stack of gold ingots for bartering, fire resistance, blocks for bridging over lava and a bow.
5. Mark both structures on the map and build a small portal hub tunnel between them once the area is cleared.

If neither structure is within 400 blocks, check the map again with the edition set correctly: a Bedrock player reading Java positions is the most common cause of a missing fortress.

Older versions

Before 1.16 there were no bastions, and fortresses used a different, coarser placement that left large stretches of Nether without one. Pick the version your world was created in and the finder switches rules; a fortress position from a 1.16 map is wrong in a 1.12 world and vice versa. Ancient debris and bastions also require 1.16 or later, so the finders hide them for older versions instead of guessing.