Assaults are an alternative way to capture forts. In an assault, Archers, Heavy Infantry and Light Infantry attempt to overpower fort's garrison in a modified land combat.
Compared to sieging, an assault can capture a fort much faster but results in more casualties. A common use for an assault is to either retake a recently captured fort or finish up a siege when the fort has been breached. An assault can also be used to capture unharmed forts by micromanaging the assault.
Assaults have hidden mechanics which severely punish sending too few or too many units which often leads to massive casualties.
Key elements for an assault
- Fort level: Higher fort levels require more units for the assault. This also causes more casualties.
- Dice: Random dice rolls determine base damage for both sides.
- Army: Non-mounted units in the army participate in the assault.
- General: Martial level increases strength of the assault which reduces casualties.
Each day, the garrison attacks all units in the assault and all units within the combat width attack the garrison. The assault ends when the garrison is defeated, the assault is defeated or the siege ends.
When to assault
Exact conditions for assaulting are difficult to calculate because of random dice rolls and multiple variables affecting each other.
Some recommendations can be given based on calculating results on different situations. This gives a good chance to capture the fort with reasonable casualties.
- Forts should be assaulted when they have less than 50% garrison remaining.
- With a breach, the fort should have less than 75% garrison remaining.
- All units should have a full strength and at least one unit should have a full morale.
- Recommended amount is ~4 units per fort level.
- General with 5+ martial needs ~3 units per fort level.
- General with 10+ martial needs ~2 units per fort level.
- Consolidating can be used during the assault to reduce casualties.
There is still a small chance (< 10%) that the assault runs out of morale before the fort is captured. However the weakened garrison should surrender on the next siege tick. 50% more units can be added to prepare for the worst case but this will increase casualties.
33% of the units can be removed if the fort has less than 25% garrison remaining (or less than 50% with a breach).
Please report results of following these recommendations in the discussion page, especially on failures.
Forts can be assaulted optimally by micromanaging the assault. Pausing the game is required to not get units locked in the assault. This works even for unharmed forts.
Both unmounted (Light Infantry) and mounted (Chariots or Light Cavalry) units are needed. Purpose of mounted units is to keep the siege active without participating in the assault.
The table below shows how many units are needed (unmounted + mounted) in the worst scenario. With average dice rolls, ~50% less unmounted units are needed.
|Fort level 1||9 + 3||6 + 4||6 + 4||4 + 5||3 + 5|
|Fort level 2||17 + 5||11 + 7||9 + 8||7 + 9||6 + 9|
|Fort level 3||25 + 6||20 + 9||13 + 12||11 + 12||9 + 13|
The table below shows how many unmounted units should be assaulting (explained later).
|Fort level 1||3||2||2||1||1|
|Fort level 2||6||4||3||2||2|
|Fort level 3||9||6||4||4||3|
- Send all units to the fort.
- Check how many unmounted units are needed in the assault army. Create a new army from the remaining unmounted units.
- Move this new army to any adjacent tile. These units get removed from the assault force.
- Start the assault and unpause.
- After a few days (or when the manpower drops below optimal), pause and move all units back to the fort.
- Also move units back if ~7 days have passed (to prevent their movement getting locked, the limit is half of the total distance).
- Select both armies and reorganize units (B). Don't merge (G) or all units get locked in the assault.
- Move one unit back to the assault army. Remember to keep one unit with a high morale in the assault. Other units can fight without any morale.
- Select the assault army and consolidate (K).
- If the assault army has too many units move the lowest manpower unit to the leftover army. This can also be used to abort the assault by moving all units.
- Select the leftover army and again move them to any adjacent tile.
- Repeat until the assault is over.
- General with 9 martial assaults a level 1 fort.
- 6 Light Infantry and 4 Light Cavalry are sent to the fort.
- 4 Light Infantry are moved to a new army and send away.
- Assault is started and the game is unpaused.
- After 5 days the manpower of assault drops below 1579.
- The game is paused and the leftover of 4 Light Infantry is sent back to the fort.
- One Light Infantry is moved to the assault army and consolidated.
- The assault army as too many units so the lowest strength Light Infantry is moved back to the leftover army.
- The leftover army is sent away and the game is unpaused.
- Repeat until the assault is over.
Dice & Damage
- An assault has a base damage of 0.08.
- A fort has a base damage of 0.18 and a 90% damage reduction.
- Each side rolls a dice from 1 to 6 every 5 days, increasing the base damage 0.02 per pip.
- A breach reduces the base damage by 0.1 which means the assault takes 33% - 50% less damage.
- A full strength assault deals damage equal 3% - 6% of maximum garrison.
- A full strength garrison deals damage equal 6.66% - 10% of maximum assault (3.33% - 6.67% with a breach).
- The garrison deals damage all units in the assault.
- Only Archers, Heavy Infantry and Light Infantry can participate in assaults.
- All unit types are equally effective at assaulting. But Light Infantry should be preferred because of their lower attrition weight.
- All modifiers such as discipline, offense, defense, morale damage taken, etc. don't have any effect at assaulting.
- An assault requires an active siege which needs at least 5000 manpower per fort level. Any units count for this limit.
- The assault stops instantly if the manpower drops below the limit.
- The army should have extra units to cover losses from the assault and also from attrition.
- Units can't retreat from the assault.
- All valid units participate in the assault, even if they are in a different army.
- The army should have units that can't participate in assaults (like Light Cavalry) to keep the siege active.
- It's recomennded to assault with only a single unit type because consolidating during the assault reduces casualties.
- Every fort level adds 1000 manpower to the maximum garrison size. Garrison size can be modified with Fort Maintenance setting.
- Every fort level increases combat width by 3000.
- Combat width sets the minimum amount of manpower required to assault effectively.
- Combat width also sets the maximum amount of manpower which can deal damage to the garrison.
- Martial skill of the general increases the assault ability by 10% per level (the tooltip states 5% per level which is incorrect).
- Assault ability can also be increased from an invention.
- Assault ability increases strength of the assault which means that less units are needed to assault effectively.
Optimal amount of manpower
Fort level and assault ability (mainly from general's martial skill) determines the optimal amount of manpower. Values are calculated below:
|Fort level 1||3000||2728||2500||2308||2143||2000||1875||1765||1667||1579||1500||1429||1364||1305||1250||1200||1154||1112||1072||1035||1000|
|Fort level 2||6000||5455||5000||4616||4286||4000||3750||3530||3334||3158||3000||2858||2728||2609||2500||2400||2308||2223||2143||2069||2000|
|Fort level 3||9000||8182||7500||6924||6429||6000||5625||5295||5000||4737||4500||4286||4092||3914||3750||3600||3462||3334||3215||3104||3000|
If the assault doesn't have enough manpower:
- Assault deals reduced damage (proportional to how much manpower is missing).
- Assault takes increased damage (proportional to how much manpower is missing).
- For example with 50% manpower the assault takes double damage. This will quickly destroy any remaining forces.
If the assault has too much manpower:
- Damage doesn't increase over the limit so damage from extra units is wasted.
- All units still take damage which results in bigger losses.
combat_width = 3 * fort_level
assault_ability = 0.1 * martial_skill + other_sources
effective_assault_strength = min(assault_strength * (1 + assault_ability), combat_width)
Fort deals damage to all units in the assault.
base_damage = 0.18 + 0.02 * roll - 0.1 (with breach)
morale_damage = base_damage
strength_damage = base_damage * fort_strength / effective_assault_strength
base_damage = 0.08 + 0.02 * roll
strength damage = base_damage * 0.1 * effective_assault_strength