Potential siege exploit to counter ranged garrison

[Mango201]

I recently saw an odd siege mechanic (vanilla Civ 6) which may have some pretty cool implications for ancient era war. Especially for circumventing the dreaded garrisoned archer.

I had an AI under a complete siege (all six tiles). The AI then somehow built a unit outside the city (and on the outside of the siege), which appeared with 1 HP.

The AI already had a garrisoned warrior when this happened. I suspect this is some kind of penalty for having too many units of the same kind in the city. But it could also be that the AI can somehow move units across a siege line, in which case it moved the warrior (which either incurred the health penalty or was on 1 HP to begin with), and then built a second unit in the city.

Is anyone aware of this mechanic and how it works? Its a fairly rare phenomenon so just wanted to see if this was a known effect. If so, I'm trying to figure out the following.

Suppose the city is besieged on all six tiles and has a garrisoned unit:

1. Can the AI move the garrisoned unit outside of the siege-lines if it is the only unit in the city.
   
2. Can the AI build a second unit inside the city? If so:
   • Can the AI chose which of the two units to move out of the city or is one of the units automatically 'shunted' out. If so, which one.
   • Note: IIRC, two units of the same type can exist on the same tile, but neither can attack until one is moved. So if the 2nd unit can't be moved out, its functionally useless. I've only ever seen this when I recruit a GP onto a tile where a GP already exists. But I suspect this is the same for combat units.

I'm hoping that either the AI can't build a second unit at all, or that the only way to do this is to have the second unit shunted out automatically.

If this is how it works, there are some pretty cool implications: You find a city with a garrisoned warrior, and surround it on all six sides. Under a 5 tile siege, the warrior could move out and a ranged unit could be built inside. This makes taking the city a much harder prospect. But under a 6 tile siege either the ranged unit can't be built at all, or the ranged unit gets shunted out of the city where it is easy prey.

Can anyone shed some light on this?

 

[Jkchart]

I recently saw an odd siege mechanic (vanilla Civ 6) which may have some pretty cool implications for ancient era war. Especially for circumventing the dreaded garrisoned archer.

I had an AI under a complete siege (all six tiles). The AI then somehow built a unit outside the city (and on the outside of the siege), which appeared with 1 HP.

The AI already had a garrisoned warrior when this happened. I suspect this is some kind of penalty for having too many units of the same kind in the city. But it could also be that the AI can somehow move units across a siege line, in which case it moved the warrior (which either incurred the health penalty or was on 1 HP to begin with), and then built a second unit in the city.

Is anyone aware of this mechanic and how it works? Its a fairly rare phenomenon so just wanted to see if this was a known effect. If so, I'm trying to figure out the following.

Suppose the city is besieged on all six tiles and has a garrisoned unit:

1. Can the AI move the garrisoned unit outside of the siege-lines if it is the only unit in the city.
   
2. Can the AI build a second unit inside the city? If so:
   • Can the AI chose which of the two units to move out of the city or is one of the units automatically 'shunted' out. If so, which one.
   • Note: IIRC, two units of the same type can exist on the same tile, but neither can attack until one is moved. So if the 2nd unit can't be moved out, its functionally useless. I've only ever seen this when I recruit a GP onto a tile where a GP already exists. But I suspect this is the same for combat units.

I'm hoping that either the AI can't build a second unit at all, or that the only way to do this is to have the second unit shunted out automatically.

If this is how it works, there are some pretty cool implications: You find a city with a garrisoned warrior, and surround it on all six sides. Under a 5 tile siege, the warrior could move out and a ranged unit could be built inside. This makes taking the city a much harder prospect. But under a 6 tile siege either the ranged unit can't be built at all, or the ranged unit gets shunted out of the city where it is easy prey.

Can anyone shed some light on this?

This is interesting. I just experienced something similar.

Medieval age - playing Norway, besieging Valladolid, which was controlled by the Dutch. Every tile surrounding the city has one of my military units in it. The Dutch have a Knight in the garrison, no walls, an outside encampment.

The Dutch build (or buy) a pikeman on their turn, which I see happening, in their city, not the encampment, which is odd, but bugs happen. Fine. BUT THEN, the KNIGHT teleports to the encampment (EDIT: through my siege lines), and the pikeman remains in the city. VERY ODD.

 

[Mango201]

I don't think that's the same thing. Military units automatically build in encampment when the city is garrisoned, just like religious units automatically build in the city if the holy site is occupied. There might have been a bug in how the animation appeared but the mechanics of what you're describing are how the game is supposed to work.

 

[Builderphile]

I have seen this happen as well. The AI builds a unit on a city that already has an existing unit and one of those two illegally stacked units moves through my units to the outside of my siege.

 

[Swissy]

AI built units in a sieged city that is garrisoned will teleport to a tile outside of the city center. This is as intended, as units stacked in a city center will give support bonus to the city defense. Most organized multiplayer groups ban this as a playable tactic.

 

[Mango201]

AI built units in a sieged city that is garrisoned will teleport to a tile outside of the city center. This is as intended, as units stacked in a city center will give support bonus to the city defense. Most organized multiplayer groups ban this as a playable tactic.

So here's the crucial question. Does the second unit teleport out? If so this can be exploited to prevent an Archer garrison as I mentioned above. If it is the first unit, random, or the AI's choice, this doesn't work.

What do you mean players ban this tactic? Since they can't ban the AI from doing anything, I assume you mean they ban other players from stacking units in a city (which then do not teleport out)?

Btw, I saw this happening again today and the unit that was teleported did not lose HP, which makes me think the unit was just injured the first time I saw this happen. This would also suggest that it is not the second unit that is teleported out.

 

[Vandlys]

So here's the crucial question. Does the second unit teleport out? If so this can be exploited to prevent an Archer garrison as I mentioned above. If it is the first unit, random, or the AI's choice, this doesn't work.

What do you mean players ban this tactic? Since they can't ban the AI from doing anything, I assume you mean they ban other players from stacking units in a city (which then do not teleport out)?

Btw, I saw this happening again today and the unit that was teleported did not lose HP, which makes me think the unit was just injured the first time I saw this happen. This would also suggest that it is not the second unit that is teleported out.

It's not the AI's choice. If you were to do the same as a player, the unit you built is automatically teleported to a viable tile. This means behind enemy lines in case of a siege. It can also happen that it is teleported out of city limits (beyond the border)! It's been this way since vanilla.

If the city weren't under siege, the AI and player could choose where the overlapping unit would move to. Since there is a choice, this could be the newly built unit, or the existing unit. Since under a siege there is no viable tile, there is no choice, thus immediately on finishing production, the built unit is put on the nearest viable tile. This can even be across the water without having researched Shipbuilding (if I'm remembering the tech correctly).