Genshin Impact Trial of the Bastion: Three-Dimensional Front Gameplay Guide

Stage IV of Trial of the Bastion, called Three-Dimensional Front, unlocked on September 10th, 2026 and brings the first airborne threat in the event. Ground traps alone no longer hold the line, because Winged Halberd-Knights fly over them and drop straight onto the approach to your stronghold. The stage runs for three waves, and every enemy you kill adds to a single score total that decides how many reward tiers you unlock.

Quick answer: Talk to Talalikhin, pick Stage IV Three-Dimensional Front, then build Pulling Mechanisms and Impact Shields at the chokepoint with Suppression Device: Blaze and Suppression Device: Faster Blaster behind them, adding Explosive Barrel Devices with the 650 construction materials you earn after each wave. Clearing all three waves with a score around 7,700 unlocks every tier.

What you need before Stage IV appears

Trial of the Bastion runs from 2026/09/07 10:00 until 2026/09/17 03:59 server time. You need Adventure Rank 20 or above, the Archon Quest Prologue: Act III “Song of the Dragon and Freedom,” and the “Gunfire in the Silent Lands” quest from Archon Quest Chapter VII: Act I “Everwinter Without Mercy.” The event’s own quest, “A Grueling Combat Simulation,” opens the full set of trials.

Five trials unlocked one per day over the event’s first five days, and each one only becomes available after you finish the one before it. So if Stage III is still sitting unfinished, Three-Dimensional Front stays locked no matter what the date is.

The whole stage takes place in the Shadow Realm, which is why you are handed a firearm loadout instead of your usual party. You control the Traveler, swap between firearm elements as needed, and restock from ammo crates scattered around the arena.

Starting the Three-Dimensional Front challenge

Open the event menu and teleport to the Trial of the Bastion location in Snezhnaya. Talalikhin is the NPC who runs the combat simulation, so speak to him and confirm that you want to begin.

In the challenge list, select Stage IV, Three-Dimensional Front, and check the loadout panel before you hit start. The screen also shows your Challenge Record for the stage, which sits at 5,600 until you beat it.

Trial of the Bastion challenge list with Stage IV Three-Dimensional Front selected and loadout shown — Stage IV selected in the Trial of the Bastion menu, with the Three-Dimensional Front lineup and loadout before the challenge starts. Image: HoYoverse

Read the tutorial pop-up that appears after the arena flyover. It covers the Winged Halberd-Knight, the flying enemy that defines this stage, and it is the only warning you get about its approach pattern.

Use the preparation timer to collect ammo from the crates on the map before you spend anything. Your stronghold starts at 20/20 HP and your score starts at zero, so nothing is lost yet.

Mechanisms available in Stage IV

Three-Dimensional Front gives you five build options, and all five have a job in a clean run. Placement tiles are marked with blue rings, and you pay construction materials for each one you drop.

Mechanism	How to use it here
Pulling Mechanism	Gathers advancing enemies into a single spot so your turrets and barrels hit a cluster instead of one target.
Impact Shield	Blocks the lane and holds enemies short of the stronghold while everything else fires.
Suppression Device: Blaze	Your main damage turret. Place it behind the shield line so it keeps firing while enemies are stalled.
Suppression Device: Faster Blaster	Second turret type, useful for covering a different angle of the approach rather than doubling up on one lane.
Explosive Barrel Device	Burst damage on clustered enemies. Best added from wave 2 onward, next to a Pulling Mechanism.

Note: You are not locked into a layout. Standing next to a built device shows a Remove prompt on F, and the energy value attached to it is displayed right there, so a misplaced turret costs you time rather than the whole run.

Defend your stronghold prompt with the F remove option highlighted on a built device showing 90 energy — The F prompt for removing a built device, shown with its 90 energy value as the wave warning appears. Image: HoYoverse

Wave-by-wave plan for Three-Dimensional Front

Wave 1: build the chokepoint

Spend your opening budget on Pulling Mechanisms and Impact Shields at the point where enemies funnel toward the stronghold, then set Suppression Devices behind that line. The first wave is the least dangerous of the three, so treat it as a test of whether your turrets actually reach the path enemies walk.

Hold a position where you can see the whole approach and shoot anything your mechanisms leave alive. Clearing the wave pays out 650 construction materials, which is your budget for the next round of building.

Player aiming a firearm at enemies as an explosion goes off during wave 1 of 3 — Wave 1 of 3, with the Traveler aiming into an explosion on the enemy approach. Image: HoYoverse

Wave 2: airborne enemies and the first elites

Before wave 2 starts, add Suppression Devices and Explosive Barrel Devices to the layout. This wave mixes ground enemies with flying Winged Halberd-Knights and elite opponents, and an Airborne Opponent Inbound banner tells you when the flyers are on their way.

Airborne Opponent Inbound banner on screen as the player turns to face a flying enemy — The Airborne Opponent Inbound warning during combat, signalling a flying Winged Halberd-Knight. Image: HoYoverse

Flyers are your job, not your turrets’. Swap to a firearm and shoot them down as they cross in, and leave the ground line to the shields and suppression devices. Elemental reactions still work in this mode, so pairing your firearm element with a grenade of a different element clears clustered ground enemies faster.

Wave 3: rearrange, then hold

The final wave is where the full 7,700 score is won or lost. Use the prep window to remove devices that never fired during wave 2 and rebuild them closer to the lane the enemies actually used, then top up your ammo from the crates.

Wave cleared screen with the F Remove prompt highlighted over a placed mechanism — Between waves, the Remove prompt lets you pull a placed mechanism and rebuild it on a better tile. Image: HoYoverse

Wave 3 throws extra elite opponents at you on top of the regular mix, and they arrive without much spacing. Keep your distance from the front line so the Impact Shields absorb the pressure, and use grenades on groups rather than single targets.

Score tiers and how to confirm you unlocked everything

When the third wave ends, a Challenge Complete screen shows your final score with the stage’s three objectives listed. A score of 7,700 checks off all of them, well clear of the 5,600 record the stage starts with. If any objective is still unmarked, the score was not high enough and you can rerun the stage.

Rewards do not arrive automatically. Open the Challenge Rewards menu from the event page and claim each tier you earned.

Reward type	What you get
Currency	Primogems and Mora
Enhancement	Mystic Enhancement Ore and Sanctifying Unction
Weapon	Weapon ascension materials

Why the run fails

There are only a handful of ways Three-Dimensional Front goes wrong, and most of them trace back to the flyers.

Winged Halberd-Knights ignore ground traps entirely. If nobody is shooting them, they reach the stronghold and chew through its 20 HP.
Spending every construction material before wave 1 leaves no room to react to the airborne and elite spawns later.
Turrets placed off the enemy route contribute nothing. If a device never fires during a wave, remove it in the next prep window.
Running dry on ammo mid-wave. Crates are on the map for a reason, and the prep windows are the cheapest time to use them.

Stage V unlocked on September 11th, 2026, and the whole event closes on September 17th, so there is time to retry Three-Dimensional Front until the score lands where you want it. Each attempt keeps your best result, which means a failed run costs nothing but the time you spent on it.