The Tech Center Building
Research Queues
The Tech Center is where every research tree is worked through, and it scales up to three simultaneous research queues as your account grows: the first Tech Center unlocks around HQ level 7, a second becomes available after clearing District 102 (typically a small real-money purchase), and a third at HQ level 30. Each additional queue lets you research a different tree in parallel — a common split is running the badge-free trees (Development, Economy) continuously in one queue while reserving a second for badge-heavy trees timed to Alliance Duel windows.
The Research Trees
Development
No badges requiredFocused purely on making everything else faster: Construction Speed and Research Speed nodes, Fast Builder and Research Enhancement tiers, and an Extra Barracks unlock around HQ 20-25 for a second troop training queue. Because these bonuses compound across every future upgrade, this is generally the tree to prioritize first and keep running continuously.
Economy
No badges requiredBoosts resource production, management, and storage — Extra Farmland, Iron Mine, and Refinery unlocks give more resource-production building slots, while Food/Iron/Coin Output tiers add percentage production bonuses. Commonly paired with Development in the same badge-free queue.
Heroes / Units (by troop type)
Boosts hero and troop stats, split into three separate lines matching the three troop types — Tank, Aircraft, and Missile Vehicle. Each line follows its own short chain (for example, the Tank line runs Tank Mastery into Cannon Enhancement or Armor Hardening, then Track Fortification). Since only one troop type is usually your main squad, most players push only the line matching their main squad and leave the other two alone.
Special Forces (Unit X — the T10 Gate)
The path to unlocking T10 troops. You don't need to max the whole tree — just four final gate nodes: Advanced Protection, HP Boost III, Attack Boost III, and Defense Boost III. The final research alone typically costs 500 million-plus coins, and requires HQ level 30 and Tech Center level 20 to even begin the last stretch. Completing it also unlocks Damage Reduction x2 and a Morale bonus alongside the T10 unlock itself.
Alliance Duel
Valor BadgesSpent using Valor Badges earned from the weekly VS (Alliance Duel) event, this tree increases the points you earn during Alliance Duel and improves the reward chests you get from it — so investing here pays itself back through better weekly rewards. Because Valor Badges are earned through VS participation, many players hoard them through the week and spend them specifically on VS Day 3 (Wednesday), when the Alliance Duel research phase lines up with badge-spending value.
Defense Fortifications
Mostly a late-game tree, with one notable early exception: its first node adds an extra hospital slot, significantly boosting troop recovery capacity. Most players take that one node early and leave the rest of the tree until much later.
Intercity Truck (Units tree filler)
A lower-priority tree that mainly matters for scoring points during specific Alliance Duel days rather than for raw account power. Most players fill this in with spare research time once higher-value trees are underway, rather than actively rushing it.
Age of Oil
Unlocks after Season 2, once the Tech Center reaches level 30 and Special Forces is roughly 40% complete. This tree introduces Oil as a core resource and is required for the "HQ Expansion" upgrade that raises building level caps past 30 (up to 35) — which in turn is a prerequisite for T11 troops from Season 4 onward. Once this tree unlocks, Oil Wells research becomes a priority since oil quickly becomes a bottleneck resource.