using military "wall" to stop AI CIV expansion

[sozinsky]

I recently started using this strategy to stop AI CIV expansion, and wanted to get some others opinions on it. (I'm sure lots of people have tried it).

In my current game, I'm sharing a reasonably large continent with four other civs. Early on I decided that I was sick of AI CIV settlers trying to settle my land, so, after grabbing a big chunk of the continent ( about 1/2 ), I built a bunch of military units (spearman, mostly) and physically lined them up in a big wall from north to south.

I'm at peace with all the other CIVS, so, as a result, I occasionally see some settlers bumping up against my wall, but none ever manage to get through.

Any thoughts about this strategy? Because I'm still a despot, and because it takes a fair amount of units to create the wall ( my wall is 2 units thick ), I can imagine my population becoming unhappy if I ever move on to a different govt....

Thanks!
sozinsky

[Aeson]

One way to avoid the costs involved in using something like this in a Democracy or Republic is to use captured workers instead. It usually is pretty easy to get 100's of them, and they don't cost any maintanence. Of course they only would work for this in peacetime.

[solo]

I also use this a lot and recommend it highly, though I use the cheapest units, and try to include workers actually doing jobs, to get something extra while maintaining the blockade.

The AI do not give up easily, in their attempts to get a round a wall, so I always leave an opening somewhere, that they can rush for, and block it just as they arrive. The longer you keep their settlers pre-occuppied this way, the longer you deprive them of extra cities, an added benefit. Plug holes long enough and you will be rewarded by seeing these settlers throw up their arms in frustration!

One other point is that I have never had an AI sneak attack me while any of their vulnerable settlers were on my turf.

[planetfall]

Have been using wall concept, but sometimes use single line instead of double line. For short sections it does not matter but single seems to be better for longer lines. See gif for example of 2 lines.

However, some cautions:

1. Probably won't have time to create wall at higher levels.

2. If use wall, protect sea leapfrogs:
a. blocking with galleys doesn't work because AI can sail in open sea,
b. privaters are good for messing up AI expansion

3. Until build wall can always challenge AI for crossing line

4. Expect some to get thru. Limit value of city by putting one of yours nearby and build culture.

5. If AI builds a city in a strange place, it is probably because there will be strategic resource in that spot later.

6. After wall and sea borders protected a line of privateers about 8 tiles apart is usually sufficient to keep AI from leaving their world and sailing to plant in yours.
You will need barracks nearby as privateers are heavily hit by return fire.

7. I usually use cheapest units for wall, warriors.

8. Alternative to solid wall is, line of warriors every two tiles, with horsemen
playing safety and plugging the gaps until the wall is secure. This strategy is helpful when don't want to buy all those soldiers and need other development first.

9. Since the AI counts the number of military more than the strength of military, the wall usually stops AI wars with a most civs.

Let us know what else you discover.

[Harovan]

I don't build a wall, but use to block the wandering settlers either with captured workers or (if I still have none) with 3-4 horsemen (from my "national guard") per party. That's enough to block the settlers. Meanwhile, I rush with my own settlers to the suspected AI destination. If they see, that it's occupied, they usually give up and go away.

[godinex]

I prefer the single line, is always the best way.

[Willem]

Boy, all this sure sounds tedious. And not at all practical on the continent maps I've been playing. Surely there should be a better way! Although I kind of like the new Zone of Control rules, I really wish they could have kept the old ones in for at least the Fortress.

I recently had a game where India had a steady stream of War Elephants strolling through my territory. I had 5-6 Knights that I kept manuevering to block the path of one of them. But in the meantime, 3 more had just passed by. Talk about a lesson in futility! I finally got annoyed enough that I just quit the game.

There has to be a better way!

[Purest Warrior]

One settler can actually be kept away with three units that are moving to block the intended path, six can effectively block two settlers, nine can block three, and so on until you actually have human wall, hand in hand, circumscribing the "earth.

[JFB]

Hmmm ... interesting discussion on walls. Some things I have noticed in my games ...

I was Greece, Rome to my south, Russians to my south-east, the game leader France just below both of them. France decides to declare war on me and I send units out on hills to hopefully stop their military. They have a ROP with Russia, so I have a four-tile border to worry about.

Civ II mistake ... I forgot, no ZOC so their 20+cavalry ran right past me and razed alot of my cities before I could counter ... OOPS.

Since the game was already lost, I decided to go back and try to stop this invasion ... I line my border with russia with everything I've got, three mountains and a forest full of Infantry, Rifleman, etc. etc. and keep a few cavalry in a city behind to play mop-up if anything gets through. Well, a few of the cavalry show up just as before, but then a turn or two later the 20+ cavalry appear in the jungle on my border with Rome!!! I was worried, even though now I could react and did ... but luckily this pissed off Rome enough that they declared war on the French as well and France had more immediate troubles than to send all it's units to me .. whew!

Next game, time to invade China, can't remember who I was playing, but I set up a wall but had just one spot in their territory they could get through when war was declared so that they can't counter-invade my capital. Well, they didn't even try to counter-invade, and instead tried to come after me through the hole, way away from any threat to my territory.

So here is a tactic I use successfully, I spread out my defense and keep offense (hopefully fast-moving) right behind the lines to attack if they break through the line of defense. If you keep offense AT the line and attack, when they win and move in front of the line they are more vunerable. I like to build roads the tile immediately behind the line to move my offense to any trouble areas, as well as reinforcements. In real life, in Berlin, the East Germans had a road running right behind the wall to rush military around as need be. I guess my visit to Checkpoint Charlie inspired this strategy!

I like to keep stacks of equal amounts of units across all tiles so if there is a particular weak point the computer keeps going for, I can continue to shuffle units towards the problem. For example, if I have six tiles of two defensive units each, and the computer hits and destroys one unit on the fifth tile, I shift one guy from 4 to 5, one from 3 to 4, etc. etc. and then put the next reinforcement on 1. Meanwhile, I have offensive units right behind the line that can quickly come in and attack if the enemy breaks through. Also, if I have a weak terrain square or a resource square, I might overbalance that stack a little.

So, defense needs to be broad, even though it is weaker at every point, you suppliment some offense right behind the lines to plug the holes when they happen and eliminate the invaders.

Offense needs to bring all its power on a single point, so one big stack that has a few strong defensive units for the whole stack. It's like in AOE when you have all your ships attack one ship at a time in order to eliminate how many hits the opponent is capable of delivering, or keep phalanx defending in front of your attacking bowmen. Broad defense, sharp and focused offense

Anyway, I notice the AI seems to respect a "show of defense". A line of troops seems to be quite a deterrent and they will quickly decide not to even try to get through it. The AI almost always goes for your weakest point, even if it doesn't have much strategic purpose. So if you use this to your advantage, you can seemingly give the computer a way through but have an ambush prepared on the other side!

Another thing was it was quite fun to move a line of defense turn by turn toward the enemy capital! Then when all is secure, move in the cavalry! Maybe this advancing line of defense is a good way to stop counter-invasion since they can't get through to your territory????

OK I now officially feel like I've rambled ... it's late, so if anybody gets anything from this let me know ...

Time for bed ... or one more turn !!!!
- JFB

[planetfall]

Ok, forgot some important concepts about using the wall:

1. Your side has roads/railroads all over the place.

2. Keep the other side as undeveloped as possible to slow down advances, even if it is inside your city borders. Solid front is more important than losing a bit of value from a couple of tiles.

3. Have a few backup up offense a few tiles back for security.

4. Regularly keep a few recon patrols working on the other side of the wall so you aren't surprised with 20 units come at you.

5. If the other side of the wall is a jungle, you can make wall every other tile and AI seldom wants to fight thru the jungle to get to you

6. I have found the AI is slower to start offense if the other side of the wall is fairly wide. Usually I have a few tiles between their area of influence and mine, and at least one area about 3x3 open that they just don't want to settle in because they are trying to find a hole in the way. The settler teams run around in all that open space for turn after turn after turn and don't learn of the wall. Shucks, breaks my heart.

7. Use your city centers as part of the wall.
You probably have some unit policing your city anyway, so put the wall thru the middle of the border city line.

I think that is everything, but may still have missed something. It would be nice to have a land based privateer to pick of these settler pairs. I am thinking of installing some mod paks so I can do that, just for the fun of it.

Lunch is over, later dude.

[Unregistered]

Originally posted by Willem
Boy, all this sure sounds tedious. And not at all practical on the continent maps I've been playing. Surely there should be a better way! Although I kind of like the new Zone of Control rules, I really wish they could have kept the old ones in for at least the Fortress.

I recently had a game where India had a steady stream of War Elephants strolling through my territory. I had 5-6 Knights that I kept manuevering to block the path of one of them. But in the meantime, 3 more had just passed by. Talk about a lesson in futility! I finally got annoyed enough that I just quit the game.

There has to be a better way!

I agree, there SHOULD be a better way. Unfortunately that will require some code changes by Firaxis. Even more unfortunately, to do it right will probably require such major changes & testing that it will probably never happen. I believe this because I suspect that the current ai would be unable to handle the simple version of changes that would just boot them out of our territory. Based on what I've seen, it would just keep trying, leading to wasted effort on its part & annoyance on ours. (Ok, for the 100th time, GET OUT OF MY TERRITORY!!!) Although, to give it some credit, once you've constructed your 50 unit 'wall' across the middle of your country, they seem to get the idea and quit trying. And fortunately, it doesn't seem to bother the civs that you have a right of passage with.

Anyway,

[Willem]

Originally posted by Unregistered


I agree, there SHOULD be a better way. Unfortunately that will require some code changes by Firaxis. Even more unfortunately, to do it right will probably require such major changes & testing that it will probably never happen. I believe this because I suspect that the current ai would be unable to handle the simple version of changes that would just boot them out of our territory. Based on what I've seen, it would just keep trying, leading to wasted effort on its part & annoyance on ours. (Ok, for the 100th time, GET OUT OF MY TERRITORY!!!) Although, to give it some credit, once you've constructed your 50 unit 'wall' across the middle of your country, they seem to get the idea and quit trying. And fortunately, it doesn't seem to bother the civs that you have a right of passage with.

Anyway,

I don't think it would require that much in the way of coding changes. All they have to do is bring back the old rules for certain situations. I think at the very least Fortress should work the way Zone of Control used. Sometimes I feel when they changed some of the rules, they ended up "throwing the baby out with the bathwater".

[Kc7mxo]

The loss of ZOC is one of the oddest changes in civ3, and it fundamentaly changes warfare.

honestly, i think this hurt the ai. while you could use spies to slip through by enemy units in civ 2, spies and other units no longer exist. if i desire to, i can completly bypass enemy units on my turn and attakc the jucy targets, while the ai seems to be more interested in wiping out my military.

i agree that fortresses, at the very least, should have zoc. as of now, what use are they really? they don't seem to give a very high defensive bonus, and take too long to build. when i read the manual, it said that they gave units iwthin them ZOC, and I at first assumed this was civ 2 zoc.

one of my bablyonian empires suffered serios setback because i only built two forts along a four square border. . . .

[Willem]

Originally posted by Kc7mxo

i agree that fortresses, at the very least, should have zoc. as of now, what use are they really? they don't seem to give a very high defensive bonus, and take too long to build. when i read the manual, it said that they gave units iwthin them ZOC, and I at first assumed this was civ 2 zoc.

And the AI rarely even attacks them. At least it's now smart enough to realize when the odds are against him, so quite often it will completely ignore a fortress and head for an easier target. If the game still used the old rules for them, then the AI would be forced to attack in some situations. Which is what they're supposed to be for in the first place. Fortresses have become nothing more than lookout posts IMO.

[Purple]

The double line in the graphic is not really double. It's actually only one-tile deep, but the diagonal arrangement of the tiles gives the impression of greater depth.

Notice that the number of units is the same in both diagrams. Killing one of the units creates a hole in either arrangement.

Anyway, I have used walls when I get tired of blocking with a smaller number of units (much as Purest Warrior described above). The big advantage of walls is that you don't have to be as vigilant.

If you want to be less passive, a more active variation of blocking is herding, where you arrange up to five units in a V-shaped formation to control the possible movement of an AI unit. Almost always the AI will move somewhere during its turn, so if you restrict its choices, it will move in the direction you herd it.

[JFB]

Yeah, purple, I like the term "herding" ... has to come from a fellow Texan! I'm a long, long way from home ...

I have successfully herded settlers in the early game to less desirable city spots. The AI will build on the first half-decent piece of land it lands on, so I herd them away from the goodies and rush a settler in.

[Dodgy Geezer]

I am a big fan of both herding and Mil-walls. I hate having to tell the AI to get orf my land every go, especially as sometime the answer is WAR!!!. As a relatively peaceful player I find that both strategies are essential for keeping and maintaining a big empire.

Herding is great in the early game - if you are an expansionist you can even use three scouts to hold up a AI settler. But even without them it relatively easy to put warrior lookouts on strategic mountains and then move/fill the gaps as necessary.

I have noticed that the AI eventually gives up if you herd them enough.

Since I turn off enemy moves to speed things up, I find that Mil-Walls are great for stopping mass incursions. In the attached picture I set up a total of three Mil-walls to prevent my Persian neighbours (who were coming second in the world after me) from gaining access to the rest of the map. This lasted about five hundred years until I finally slipped up and had sixty cavalry on my hands. Still, after a bit of judicious herding I managed to get them cornered on some flat land and bang, suddenly they didn't have an offensive capability any more, and I had a new leader to play with!

[lorddread]

I used to use the wall in all the other civ games (civ II, ctp) but here the game can still mess with you. What it can do is this: When it encounters your wall, it can make a settler form a city right next to it. This way your soldiers are in its territory. This forces you to move you wall. It can keep doing this all the way to your cities.

[planetfall]

Play it back. In those push back scenarios where you don't have a row of cities as a fixed border behind your wall, put in a wall segment of throwaway cities. Point is to slow down AI while working on more important issues.

Pick a spot where you want to push back and
plant cites 4 tiles apart. Put in a warrior, temple and library. They will find it hard to move. Useful to slow down expansion on a land mass where AI is expanding too fast and where
you want to delay and distract AI. Does not matter if city reverts, this is a slow down strategy and not a gain space strategy. It helps reduce area of influence of cities that are too big.

I have learned from watching the AI the proper method is:
1. naval transport at source city
2. settler and warrior at source city
3. Turn 1-- load gallery{transport}
4. Turn 2--
a. move gallery
b. unload settler & warrior
5. Turn 3--
plant nuisance city.

Only way I have found to defeat this strategy is:
anticipate, anticipate
double check wall is solid, tiles in area of influcence but NOT in city boundaries are holes and will be tested by AI
protect coast by transports or privateers
forcing AI transport to detour so can't finish in one turn


NB: another effective AI strategy to exploit wall holes

I have learned from watching the AI the proper method is:
1. naval transport at source city
2. 2 settlers and 2 warriors at source city
3. Turn 1-- load gallion{transport}
4. Turn 2--
a. move gallion
b. unload settlers & warriors
5. Turn 3--
plant nuisance city.
if move was less than full for gallion,
for last move, move into nuisance city
so not visible on water
6. turn 4--
move down coast 4 squares
unload 2nd settler and 2nd warrior
7. Turn 5--
plants 2nd nuisance city


AI is definitely willing to lose one transport for 2 new cities. Either detroy
with privateers or beat to punch.

Sometimes opening apparent holes in the wall by moving wall pieces into the city line and then restoring when AI moves pieces to get through opening buys time. The AI thinks it can get behind the wall and keeps sending too many settler pairs trying to find a hole. A solid line leads it to turn aggressive sooner. A wall with an apparent gap at one end, oh, plugged by the time you got there, and an apparent opening at the other end gets the AI moving settler pairs back and forth along the line. Fun to watch and does seem to delay expansion in other areas where you may not be as ready for them.

[Arrian]

Personally, I spend my early game resources on settlers so that I grab the city sites I really need, and accept a certain amount of AI ICS. In the mid game, my resources are spent building improvments and wonders. In the late game, I DO build a wall - a wall that moves and kills, composed of dozens upon dozens of Modern Armor. But that's another story...

-Arrian