How to control border entry by AI units

[lummoxybez]

I keep encountering the situation where the AI floods units into my territory when they don’t have a RoP with me.
If I ask them to leave it invariably ends up with a DoW, and even if I come out on top it’s usually annoying.

The AI is usually heading towards barbs or another AI that they are at war with.

The last time I gave them a RoP to help them get to their destination quicker they DoW me when all their units were deep into my territory and it was carnage.
(The player would be penalised for cheating like this, so how does the AI get away with it?)

Anyhoo, does anyone have any tips on how to handle this please?
I successfully used a choke point in one game, but that isn’t always possible.

 

[WeirdoJoker]

I keep encountering the situation where the AI floods units into my territory when they don’t have a RoP with me.
If I ask them to leave it invariably ends up with a DoW, and even if I come out on top it’s usually annoying.

I wonder the same thing myself, oftentimes, and am interested to know the best way to deal with it.

Spoiler :

Fortunately, the last time the AI stationed its units in my territory, it was not very many and was on the edge. I asked them to leave, they DoW, and I pummeled them to death. They did not realize I was playing for Conquest/Domination and so was happy to go to war. Won my high score that game.

 

[Nathiri]

Well some terrain improvements like colonies and outposts blocks AI units. Using these in conjunction with units, you could block off your borders.

 

[justanick]

Having a sufficient offensive military would help. If they do declare war on you, then you can reach a favourable outcome. Another option would be to build a wall of units, one per tile at the border so the border cannot be penetrated without attacking you. Works best if the border is short.

 

[lummoxybez]

Yeah, I’ll try the wall of units approach I thInk. It’s a 4 tile isthmus so it is doable.

The only thing is that their “RoP-breaching-DoW shenanigans “ caused a war that ran on for 2000 years. Now I’ve whittled down the Aztec army to the bare bones I’m about ready to hit Monty with all my knights and immortals, so the isthmus is gonna be irrelevant.

 

[tjs282]

Yeah, I’ll try the wall of units approach I thInk. It’s a 4 tile isthmus so it is doable.

At risk of necro-ing this thread, I would point out that the isthmus does not necessarily have to be between you and the 'invading' Civ in order to 'block' their access to your territory. It can instead be between you and the Civ that the invader wants to attack. This is because the AI always knows where everyone's visible units are at all times, so will not send its units on a GoTo-path that is (currently) blocked off.

Spoiler Illustrative example :

I played a game a couple of months back on a (randomly rolled) Large 60% Archi-map (as the Zulus, at Emp), with the Romans/Carthaginians to the south, and the Aztecs to the north of me. There was a 2-tile Hill/Mountain choke between my 'island' and Monty's, and a 3-4 tile Plains/Desert 'semi-choke' between me and Jules. Needless to say, Monty DoW'd me early on (forcing me into a Despotic GA, when one of his Jags finally succeeded in committing suicide-by-Impi ), but I recruited Jules to help me fight him, and that worked out pretty well. I gave Jules an RoP, but all the towns along his route were lightly garrisoned to discourage friskiness.

Once we'd pushed Monty back to the northern choke (where he'd already built a convenient Hill-town, which I captured), I closed it off completely, and all the Roman troops which had been marching north(west)wards, immediately turned around and start heading south(east) again. So at any given point I could send those troops in whichever direction I wanted (and hence thoroughly separate the fast units from the slow ones), simply by opening/closing the northern choke.

This proved useful when I was finally ready to DoW Jules in the mid/late-Medieval, because I had been able to ensure that for the most part, he had only been able to use Horses/Knights to take the Aztec towns — which for the Romans were almost totally corrupted. So even though he'd held them for multiple turns (and sold me the Aztec Horses!), he still hadn't built (m)any decent defenders up there —which made it much easier for me to take the formerly Aztec lands from him. My newly built vCavs carved through his meagre colonial garrisons, while the city I'd built up near the southern choke was heavily garrisoned with my eKnights, Muskets and Cannons, which easily repelled his incoming Maces, LBMs and Muskets, plus the occasional Knight.

 

[r16]

playing at monarch ı think the players could manage some tons of units out of cities to form indeed a wall . Slave workers are ideal . And preferably not following your borders but a straight line somewhere inside . So that if it comes to war , you can concentrate at someplace easier and quicker .

 

[vorlon_mi]

r16, that's a great point. Any unit can be used to form a "human wall." Extra slave workers that are not being used to clean up pollution can be parked on tiles to form a choke point. I have also used them as a "moving barricade" along the coast if I see an AI ship approaching with a possible invasion fleet. They usually are not bringing marines, so the AI cannot land on a tile with a worker on it. Your blockers can slide down the coastal roads to stay in front of the AI ship.

 

[r16]

which wakes memories of Colonization in me . Holding the shore with colonists as my cities would be soon full and adding more would just bring my efficiencies down and nothing happens . So , finally ı declare stuff and homecountry arrives and oh my , Royal ship of line does not even bother to land troops but captures them all by itself , even veteran soldiers ! But entirely correct for Civ , especially if you have rails by then .

a little extra is that a full wall can also allow to gauge the intentions of AI , you have covered every place and it's still coming on ? Well , it's indeed war . ı would let him , now that his fast units might seperate from slower ones . Am a cavalry guy , like the option of them surviving after losing the battle as they can heal after a turn or two .

 

[tjs282]

They usually are not bringing marines, so the AI cannot land on a tile with a worker on it.

I liked your post, but would point out that this sentence is not true: what makes the 'Amphibious' ability special, is that it allows the Berserk/Marine to attack a combat land-unit (A.D ≥ 1.1) directly from a boat. But any boat-borne combat-unit (A≥1) can attack/capture any non-combat unit(s) (A.D=0.0) which is/are left undefended on a waterfront land-tile. So if you are (already) at war with the AI, then whether or not its Transport(s) is carrying Marines is irrelevant.

e.g. in my current solo game, I did this with Infantries (I cratered an Iroquois Iron-Hill using my Ironclads, then captured the Workers that came to re-road it)..

So Workers/Slaves can/should only be used as blockers during peacetime. Not least because where a human would load their newly captured Slaves back onto the Transport that the combat unit unit(s) just disembarked from, the AI will likely just disband the captured Workers where they stand (it can only embark units onto ships docked in coastal towns).

 

[jarred!]

(it can only embark units onto ships docked in coastal towns).

I did not know this was a fact, but it would be more impactive if seaborne invasions by the AI weren't so pathetic.

 

[Bartleby]

So Workers/Slaves can/should only be used as blockers during peacetime.

As far as I'm aware, the AI is not familiar with the rule, and coastal workers are safe during wartime.

 

[Buttercup]

Nope, it has happened to me before. It's rare, but it is possible.

My guess is that: You know how sometimes the AI is about to attack you / sending a fleet your way, you just get that vibe & even if you agree a great peace deal with them in preparation, including alliance and trades etc & they still land to attack - I think in this scenario they will still land even if you have a worker on the destination tile, as in: then it will read that rule.

I suspect it doesn't read the rule when it hasn't decided to attack, so if you have a worker on a two-tile island with a town then that island's probably safe from becoming a target in the first place. Though I personally wouldn't risk it unnecessarily.

 

[Bartleby]

I stand corrected.

 

[vorlon_mi]

I liked your post, but would point out that this sentence is not true: what makes the 'Amphibious' ability special, is that it allows the Berserk/Marine to attack a combat land-unit (A.D ≥ 1.1) directly from a boat. But any boat-borne combat-unit (A≥1) can attack/capture any non-combat unit(s) (A.D=0.0) which is/are left undefended on a waterfront land-tile. So if you are (already) at war with the AI, then whether or not its Transport(s) is carrying Marines is irrelevant.

e.g. in my current solo game, I did this with Infantries (I cratered an Iroquois Iron-Hill using my Ironclads, then captured the Workers that came to re-road it)..

So Workers/Slaves can/should only be used as blockers during peacetime. Not least because where a human would load their newly captured Slaves back onto the Transport that the combat unit unit(s) just disembarked from, the AI will likely just disband the captured Workers where they stand (it can only embark units onto ships docked in coastal towns).

First, thanks for the correction.

Second, this gives me an idea, that was probably the origin of the "worker on the beach" comment I read in the forums when I first joined. If you want to lure an AI invasion force to land in a certain place (where you have your response troops ready), you could use a worker -- or even better, a slave worker from the nationality of the AI invaders -- as *bait*. Put the worker out there, and lure them in.
In land wars, leaving a lone worker or slave often attracts an AI attacker to leave its stack and try to capture it; where you may more easily pick it off.

 

[justanick]

As i recall it AI does not understand that workers on beaches can be attacked amphibiously by nonamphibious units.

 

[Lanzelot]

In Vanilla and PtW, it was technically impossible to capture workers (and settlers and artillery units) from a boat with a non-amphibious unit. (Also for the human player, so you can try it yourself.) This feature was added in C3C, and probably they "forgot" to tell the AI algorithms about this new feature...

I didn't know so far that the AI does it anyway, if it really wants to attack... Interesting. But I noticed in the past that if an AI is bound to attack, there must be special rules/algorithms at work: nothing will stop them at that point, not even gifting them thousands of gpt, luxes, resources, alliances...

 

[r16]

save a lot and re-load a lot offers some measure of safety . If the AI has decided to attack , going back one single turn definetely does not help . Two or three (depending on your bribes) might . If the AI decides to demand something and it's immediate war with your refusal , ı have seen putting some units into AI territory helps , because it will waste the turn demanding you to retreat . Up to a point , which ı wasn't counting but it might be 4th or 5th time ı had invaded its territory , outting two offensive units right next to its town , it cut it short and demanded something , "Give it or else" like .

 

[vorlon_mi]

In my experience, when the AI wants to attack me, it usually seems to decide where my least-defended town is, and tries to land its forces or send its fast movers overland there. If all my coastal towns are equally well defended, I can stall them by shifting a group of Cavs or Knights along from town to town. Nearly always, the attack will come. I can recall only one time where it seemed to lose its resolve, and not land its troops.

But once they've launched their fleet (Galleon and 2 Frigates), it has made the decision to attack and bribes won't change its mind until the troops are landed (and defeated).

 

[jarred!]

While seemingly overlooked on GoTM and HoF rule sets here, over at Realms Beyond they discuss two exploits you hint at: 'baiting the AI', and 'puppet strings.' Essentially, knowingly moving your troops in a manner that causes the AI to do something stupid, for your gain, is an exploit. This includes leaving a settler or worker exposed in order to trick the AI to capture it, and moving troops back and forth between towns to cause the AI to make its stacks walk in circles.