Ok, when approaching a city you have in mind to take it, you first need to see whether there is a general occupying the city. If no, move on to the next section. If yes, what you need to do if you really want the city is to get rid of the general. Rumor is your key ally here, if you have generals just use something light to apply rumour on the opposite side of your enemy whilst you deal damage to the enemy general in the city. This can not only weaken the enemy general's damage output, but also serve as a distraction where the general won't target your general, instead he will attack your weaker in range units first. This can be particularly useful when you are using fragile artillery or infantry generals. If you do not have generals, just surround the enemy general with strong units like healthy medium tanks, while you use howitzers as your main damage dealer. Of course other methods are free for usage but this is the most effective as howitzers are really good at lowering the health of cities, while medium tanks can attack again to deal damage twice when the defeat the city unit. If the enemy general is low hp, or is an artillery general, then air attacks would be good to.
Now to the main point, we can use many methods to lower the health of an open city.
1) Paratrooper spam.
A good way to lower city hp fast with your land units only can be achieved using the additional damage mechanized infantry does to stronghold units. This strategy cannot be used by players who have yet to fully upgrade their unit type for paratrooper technology upgrades. When paratrooping, all types of cities from level one to star cities(aka capitals) are suitable for attack, and the best spot to land your units will be minimally 2 hexes away from cities. Why do this as it takes some infantry movement technology upgrades? The answer is that doing so will minimize the probability of the enemy AI sensing your attack and spawning units in the empty cities for defense, preventing you from doing more damage. For level 1 cities, 4 paratroopers are enough where 3 will lower city hp and the other will occupy the city. For level 2, 7 paratroopers are needed, and for the rest just use 7 too as the maximum hexes that you can occupy to attack a city through 1 range is 6(hence hexagons lol). Paratroopers to invade cities are best used when the cities are open, and you have enough money but lack enough industry to just spam missles, or when you have to focus more on other fronts. If you have a level 3 or higher city in proximity to your desired enemy city, then do not waste your air units money, just spawn stackable mech infantry.
2)Stackable Mechanized infantry and commandos(with city stronghold bonuses)
Both have bonuses. But commandos move very slowly, so this is suitable if you have many cities in a row to occupy, when you have a city capable of spawning these infantry troops(lvl 3 or higher) and when you have money to invest in this venture. Definitely deals more damage than option one, and is highly effective in settling all kinds of cities, especially healthy cities.
3) Naval units.
If open cities just happen to be in range from non air naval units except submarines, then congratulations, as we have gotten to the most efficient way of city invasion without the need of generals. Double stacked cruisers, albeit expensive, can deal insane damage to open cities, allowing you to easily bring down a star city like washington or tokyo down to 0 hp for an easy paratroop snipe. This is very costly and can be best used with a paratroopable city near be, with control of the sea and with enough cash in the fist place lol
4)Artillery units
This is to ensure maximum effectiveness where your artillery units lower the health of cities rather substantially and quickly, letting you take the city. However artillery units deal around the same damage as mech infantry when fully upgraded, and they cannot move quickly, thus this method is only good for cities with defensive units in them, otherwise open cities are better dealt with the above options than this.
5) Generals
The best way to lower city hp, especially with a general on a terrain commando or 4 stack mech infantry. Artillery generals are capable of dealing devastating amounts of damage too, and the same for tank and navy generals. The most efficient order would be to: Use your artillery/infantry/navy general, then use other methods to lower city hp to near end(not too much though), then use your tank general to end the city hp, and with the chance to attack again swoop into the city to save on the paratrooping cost. Of course the disadvantages of this strategy is the availability of such generals in the first place, and beginner players should consider this strategy only with conquests with starting generals, not campaigns.
6) Air attacks.
Fighters are extremely cost-effective methods of lowering a near end healthy city hp to 0, or just taking a level 1 to 2 city. Not recommended if you are short of resources or if the city has air defences(lvl 1 or 2 anti air gun is acceptable). Bombers deal very slightly more damage, so fighters are wiser. Strategic bombers can get past all anti air guns, and deal quite high damage amounts to open cities. However, they are not suitable if you are short on cash and technology. Also avoid cities with level 2 or higher missile defense for air. Stealth fighters and bombers are irrelevant, costly and weak, but stealth strategic bombers are the best method, albeit being expensive. They are the optimum way to sneak full nuke damage into open cities, but if the city has up to full anti air artillery dont bother as its nuke damage reduction is minimal. Of course dont waste them on cities with little or no air defense.
7) Missile attacks
Costly on industry and tech, but super effective in lowering anti air artillery and high level anti air gun defended cities, and to some usefulness lvl 1 and 2 defended anti air missile cities. Convenient nuking methods as they do not get nuke damage deductions up to anti air artillery, but they are v costly and can only be developed late game for earlier conquests, or sometimes not at all for campaigns.
very useful guide, I like a lot! You took a long time to make this, but very help in letting us understand how to play smart
