The Prerequisite Chain, Not a Checklist
Prerequisites Are Level-Specific, Not Uniform
A common misconception is that every prerequisite building needs to match your HQ level. It doesn't work that way — a given HQ level might require Tech Center at level N, Wall at level N-1, and Barracks at level N-2, each independently. The buildings that rotate in as prerequisites are: Tech Center (required at nearly every level), Wall, Barracks, Hospital, Drill Ground, Alliance Support Hub, and your chosen Troop Center (Tank, Aircraft, or Missile).
The two-level preview rule: before starting any long upgrade, check the requirements for your next two HQ levels, not just the next one. This prevents the common situation where you finish an HQ upgrade only to discover the next prerequisite building is still several days away from ready.
Full Prerequisite Chain: HQ 2 Through 30
Sourced from a detailed community-made infographic (Aethernis, ko-fi.com/aethernis) and cross-checked internally consistent across two of their charts where the levels overlapped. This example follows a Tank-focused account — if you've committed to Aircraft or Missile as your main type, your own Combat Center requirement will show that type's building instead of "Tank Center."
| To Unlock HQ | Condition 1 | Condition 2 |
|---|---|---|
| 2 | Drill Ground 1 | 1st Squad 1 |
| 3 | Wall 2 | — |
| 4 | Barracks 3 | Drill Ground 3 |
| 5 | Wall 4 | Barracks 4 |
| 6 | Wall 5 | Drill Ground 5 |
| 7 | Wall 6 | Tank Center 6 |
| 8 | Tech Center 7 | Alliance Support Hub 7 |
| 9 | Tech Center 8 | Tank Center 8 |
| 10 | Tech Center 9 | Hospital 9 |
| 11 | Tech Center 10 | Wall 10 |
| 12 | Tech Center 11 | Barracks 11 |
| 13 | Tech Center 12 | Tank Center 12 |
| 14 | Tech Center 13 | Drill Ground 13 |
| 15 | Tech Center 14 | Wall 14 |
| 16 | Tech Center 15 | Alliance Support Hub 15 |
| 17 | Tech Center 16 | Tank Center 16 |
| 18 | Tech Center 17 | Hospital 17 |
| 19 | Tech Center 18 | Wall 18 |
| 20 | Tech Center 19 | Barracks 19 |
| 21 | Tech Center 20 | Tank Center 20 |
| 22 | Tech Center 21 | Drill Ground 21 |
| 23 | Tech Center 22 | Wall 22 |
| 24 | Tech Center 23 | Alliance Support Hub 23 |
| 25 | Tech Center 24 | Tank Center 24 |
| 26 | Tech Center 25 | Hospital 25 |
| 27 | Tech Center 26 | Wall 26 |
| 28 | Tech Center 27 | Barracks 27 |
| 29 | Tech Center 28 | Tank Center 28 |
| 30 | Tech Center 29 | Drill Ground 29 |
Other non-building milestones along the way: the Alliance Support Hub itself unlocks at level 4 (letting you join or create an alliance), Radar Station around level 6, Coins become a required resource from level 9 onward, T5 Troops unlock at 10, Ultimate Skill at 15, and Special Forces research (the path to T10 troops) at 20.
HQ 31 Through 35
| To Unlock HQ | Tech Center | Other Buildings Required |
|---|---|---|
| 31 | TC 30 | Your Combat Center (Tank, Aircraft, or Missile — whichever you chose) + Barracks (level 30) |
| 32 | TC 31 | Tank Center + Barracks + Wall (level 31) |
| 33 | TC 32 | Tank Center + Barracks + Hospital + Drill Ground (level 32) |
| 34 | TC 33 | Tank Center + Barracks + Wall + Alliance Support Hub (level 33) |
| 35 | TC 34 | Tank Center + Barracks + Hospital + Drill Ground (level 34) |
The Real Gate: HQ 30 → 31
Three Things Have to Line Up
Pushing your Headquarters past level 30 requires all of the following, not just one:
- Your Tech Center must reach level 30.
- The Special Forces research tree must be far enough along — this requirement was reduced from 80% complete to 40% complete in a later update, so older guides quoting 80% are describing an outdated threshold.
- You must then research and complete HQ Expansion, a special research item that only appears at the end of that tech tree once the above two conditions are met.
Only once HQ Expansion is fully researched can your Headquarters progress from level 30 up toward the current cap of level 35. From that point on, Oil becomes the dominant bottleneck — Food, Iron, and Coins are rarely the limiting factor at this stage.
The "HQ Expansion Lv1" research itself costs roughly 616M Food & Iron, 1.8B Gold, 4.1M Oil, and is cited at 942 days of base research time — that last figure is almost certainly a "zero speedups, zero help" baseline used to illustrate scale, not a literal wait time, since alliance help and speedup items cut it down dramatically in practice.
Age of Oil Timing
A Season-Tied Unlock, Not a Personal HQ Milestone
Age of Oil becomes available after Season 2 ends on your server — it's tied to season progression, not to your individual HQ level, so every account on the same server gains access at the same time regardless of their own HQ progress. Oil Wells are the primary Oil source: 2 are unlockable through research, plus 3 more awarded simply for leveling HQ, for a maximum of 5 total. A realistic free-to-play timeline for reaching HQ 35 without additional spending is commonly cited as landing somewhere in the final weeks of Season 4 — a long grind, but a predictable one if Oil infrastructure is prioritized early rather than as an afterthought.
A Few More Prerequisite Notes
Squads
You start with 1st Squad and can unlock 2nd and 3rd Squad progressively through play (3rd specifically needs Headquarters level 20 plus 2nd Squad's own research at 25% complete), with 4th Squad available through the Super Monthly Pass instead. Only 1st Squad typically needs active upgrading — the others mainly matter if you're specifically chasing low-cost Arms Race points or feel your account has fallen unusually behind. See Heroes for the full unlock breakdown.
Sync Building Completions to VS Day 2
If a building finishes but you haven't collected/opened it yet, it's often worth holding it and opening on VS (Alliance Duel) Day 2 — Base Expansion — specifically, since that's the day building-related actions score event points. See VS (Alliance Duel) Day-by-Day Guide for the full schedule this ties into.