Start here: plan your first battle — worked examples for land, sea and fatigue, with decisions after a narrow win.

Era of Conquest — Combat & Economy

Food, materials, and unit types

Open an owned province to choose farms, workshops, or commerce. Changing focus costs 10 gold and that province's action. Farms produce more food, workshops more materials, and commerce more gold. Focus income is additional to existing gold income and is adjusted by empire size and difficulty efficiency.

Recruit five infantry for 6 gold and 5 food; five cavalry for 12 gold, 10 food, and 5 materials; or five artillery for 15 gold, 5 food, and 12 materials. Recruitment requires room for all five and uses the province's action. The existing emergency levy adds four infantry for 6 gold. Food currently pays for recruitment; it is not deducted as recurring army upkeep.

Infantry are cheapest, cavalry add attack strength, and artillery help against fortifications. Sending part of an army automatically apportions its unit types proportionally. Check the composition and combat preview before attacking. All numerical examples below assume an infantry-only army.

The exact rules behind every attack, and where your gold comes from · Operator: Chenyjunny

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Every fight in Era of Conquest is decided by one comparison, and once you know it you can look at a border and tell in advance whether an attack will land. There is no dice roll and no hidden modifier — this page is the core comparison. Fatigue and sea crossings change the attacking force before that comparison.

What one province can do in a turn

• One action each. A province may attack, reinforce, levy, develop or fortify — once per turn, then it is done.
• A garrison always stays. You can never move your last unit out; at least 1 troop remains in the province you moved from.
• Reach. You can act on a province you share a land border with, on one connected by a short sea link, or on a coastal province within amphibious range.
• Diplomacy gates attacks. You may only attack another nation while you are at war with it. Grey neutral land needs no declaration at all.
• Moving into a captured province ends its turn too — the advancing army cannot immediately push on.

The capture formula

Note that the comparison is strict — equal is not enough, you need to exceed it. If you do capture, the troops that survive to hold the province are attacking force − defending troops − defence bonus, with a minimum of 1. That is why an attack that barely squeaks through leaves you holding the ground with almost nothing, which is often worse than not attacking at all.

If the attack fails, the defender is not untouched: their troops drop by attacking force − defence bonus (never below 1). So a failed attack still softens a province, and two attacks in the same turn from two different provinces can take a target that neither could take alone.

Sea attacks cost you part of the army

This applies to any move across water, whether it is a long-range landing or a short hop between islands, and it is the single most important thing to remember about naval play. Ten troops across a strait fight as six. It is why island nations are hard to invade and why an unfortified coast is not as exposed as it looks.

Attacking again and again tires an army

This is why hammering the same weak neighbour from the same origin, turn after turn, stops working as well as it looks: the fourth consecutive attack uses 70% strength. The third consecutive attack uses 80%. One turn without attacking removes one stack, rather than resetting all fatigue. The attack menu and the province's own info line show the exact stack count and percentage before you commit.

Worked example

A province with production 5 and 2 levels of fortification, owned by a nation at era 1, holding 7 troops. Its defence bonus is ceil(5 ÷ 2) = 3, plus 2 fortification, plus 1 era — 6. So you need to bring more than 7 + 6 = 13. Overland, 14 troops takes it and leaves you holding it with 1. With no fatigue, the minimum across water is 22, because ceil(22 × 0.6) = 14; 21 only gives 13 and fails. The origin needs 23 troops so that 1 stays behind.

Where troops come from

• Production. Every province you own adds its production value in troops at the end of each turn, scaled by your administrative efficiency (below). Production runs from 1 to 9.
• Levy. Spend 6 gold in a province to add 4 troops immediately. It uses that province's action for the turn.
• Reinforcement. Moving troops into your own province simply adds them, up to the cap of 999 per province.

Where gold comes from

You start with 10 gold and can hold up to 999. Note that the flat 2 and the era income are per-nation, not per-province: they matter enormously to a one-province nation and barely at all to an empire. That is deliberate — it keeps a tiny nation able to act.

What to spend it on

• Levy — 6 gold for 4 troops. Immediate military power.
• Develop — 6 gold for +1 production. Permanent: more troops every turn, more gold every turn, and a better defence bonus as a side effect.
• Fortify — 4 gold for +1 defence. The cheapest way to make a province genuinely hard to take. Caps at 6.
• Gift — 8 gold for +10 opinion with another nation. See the diplomacy guide.
• Instigate war — 14 gold to pay a rival to attack your enemy.
• Raise an era — 45 / 100 / 180 gold. +1 defence in every province you own and +4 gold per turn, per level. See the victory guide.

The penalty for being big

This is the most important economic rule in the game and the one new players miss. At 12 provinces each one pays in full. At 24 provinces each one pays half — meaning your 24-province empire produces the same as a 12-province one before rounding, if production is identical. Actual income is rounded per province; difficulty and economy settings also affect it. The return flattens between 12 and 24 provinces, and efficiency never drops below half no matter how large you get.

The practical consequences:

• Developing beats expanding once you are large. Efficiency scales what each province produces, so raising production on the provinces you already hold is worth more than adding a low-production one.
• Small nations are not as doomed as they look. A five-province nation is running at full efficiency against an empire running at half.
• A big AI slows down too. The runaway leader is fighting the same maths you are, which is exactly why a comeback is possible.

Reading a border before you commit

1. Look at the defender's troop number and add its defence bonus — production is visible, fortification and era are what you have watched them build.
2. Add 1, because you need to exceed, not match.
3. For a sea attack, calculate ceil(sent × 0.6); overland, use the number sent.
4. Apply fatigue next: max(1, floor(force × (1 − 0.1 × stacks))). Check that the result exceeds the defender's total. For a fatigue penalty of 30%, divide by 0.7 when estimating; adding 30% is not enough.
5. Remember your origin keeps 1 behind, so you need that many plus one sitting there.
6. Ask what the province is worth holding with the handful of troops that will survive the capture.

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