Minor AI bug I have just found

[SPQR300]

When the AI switches to mercantilism it doesn't abort open border threaties. But aborting them is vital, beause it won't get money from foreign trade routes, open boders will only feed its rivals with money. Ok, the AI shouldnt cancel the threaty if he is friendly with the other nation, or when it REALLY needs the ability to move units in the rival's land. But otherwise it should stop feeding its rivals with gold.

 

[MrCynical]

Hmm, I'm a little dubious about cancelling open borders just because you're running Mercantilism. The gain is minor at best unless there's only two or three civs on the map. Trade routes to you are unlikely to be that much better than trade routes to other AIs so you're not going to do the AI economy that much harm. It does a lot of harm to your diplomatic relations, and causes problems with unit movement and missionaries. Unless you really want to become a shunned nation I wouldn't close the borders unless there was only me and the other AI on the map.

Closing borders, even under Mercantilism is far from vital, and I can easily see the AI managing to get itself blocked in like this. I'm not at all convinced a change here is a good idea.

 

[SPQR300]

You are wrong, once you switch to mercantilism it means you hardly have good trade routes. If you have good realtions and treade routes you won't switch from free-market to mercantilism. Once you have switched to merc. you won't get any foreign trade routes, but your rivals will from you. And don't underestimate the significance of trade routes. If you dont cancel the routes you give your rivals 10-15gold/city/turn.(in middle ages, and you get even more 20-30 in coastal cities) Open borders are extremely important economic elements of the game, you shouldn't open border with everyone anyways...

 

[MrCynical]

You seem to be confusing the penalty you get from Mercantilism and the penalty your rivals get from you closing borders. YOU get a massive penalty to trade of, yes, up to 20-30gpt per city from it. The AI won't get anywhere near this penalty from you closing borders unless you are the only other civ on the planet. In any other circumstances the AI can take its buisness elsewhere, and form trade routes to a different AI. Yes, it'll lose a few gpt since it wouldn't have been trading with you unless it was the most profitable option, but nowhere near the amount you suggest. If it has a 10cpt trade route to you which is now blocked, there'll usually be an 8 or 9cpt alternative from a 3rd AI it can switch to. Its loss is therefore minimal. I personally take the view that it most cases closing borders is going to do you more harm than the AI. Yes there are circumstances where closing borders is the right strategy, but they are far rarer than you make out and I can easily see the AI messing itself up with this.

you shouldn't open border with everyone anyways...

Another point I regard as very debatable. Unless I'm blocking off land with my borders they should always be open in my opinion.

 

[SPQR300]

You seem to be confusing the penalty you get from Mercantilism and the penalty your rivals get from you closing borders. YOU get a massive penalty to trade of, yes, up to 20-30gpt per city from it. The AI won't get anywhere near this penalty from you closing borders unless you are the only other civ on the planet. In any other circumstances the AI can take its buisness elsewhere, and form trade routes to a different AI. Yes, it'll lose a few gpt since it wouldn't have been trading with you unless it was the most profitable option, but nowhere near the amount you suggest. If it has a 10cpt trade route to you which is now blocked, there'll usually be an 8 or 9cpt alternative from a 3rd AI it can switch to. Its loss is therefore minimal. I personally take the view that it most cases closing borders is going to do you more harm than the AI. Yes there are circumstances where closing borders is the right strategy, but they are far rarer than you make out and I can easily see the AI messing itself up with this.





Another point I regard as very debatable. Unless I'm blocking off land with my borders they should always be open in my opinion.

I was talking ALL THE TIME about what the AI should do, not what I should do. If the mercantilist AI closes his borders with me, it doesn't lose anything except for the ability to move in my lands, but I do lose gold,(even if I have trade routes with others, ok, I don't lose so much gold then, but I still lose some). While the AI loses nothing. If I am no mercantilist then I only don't open borders with civilizations that would profitate much more from the treaty and are real rivals. But when you are in mercantilism which doesn't let you have any trade routes you don't want your rivals to get free gold, maybe your allies, but not your rivals.

(I hope you know that when you are in mercantilism and you have open borders with someone he gets all the trade route money in his cities, but you dont get any...)

 

[MrCynical]

(I hope you know that when you are in mercantilism and you have open borders with someone he gets all the trade route money in his cities, but you dont get any...)

I'm well aware of this, and have pointed this fact out in several discussions on mercantilism and trade routes in the past.

I was talking ALL THE TIME about what the AI should do, not what I should do.

So what? The same strategy works, or doesn't work, for humans and AI alike. If it isn't a good strategy for the human player (which is the perspective I've been discussing it from for simplicity's sake), it isn't good for the AI. If it makes you happier I'll explain completely in terms of AIs, but it makes it more confusing.

AI 1 switches to Mercantilism. It loses major amounts of cpt in exchange for free specialists. It also closes borders with AI 2. AI 2 had trade routes to AI 1, but now has to reroute them to AI 3, AI 4, AI 5, etc. Its cpt loss is minimal, since it is only losing at most 1 or 2 cpt for each trade route that went to AI 1. Since the number of trade routes at the stage of the game where Mercantilism is likely to be used is probably only 2 per city, the net commerce loss is quite small.

OK, so AI 1 has done at the very most about 20 cpt in total damage to AI 2's economy by closing borders, and probably less than that. In return AI 1 cannot move military through AI 2's territory (may or may not be a problem depending on the map), cannot send missionaries (may or may not be a problem depending on religious status and forethought), and is less popular diplomatically (always a problem). I personally do not consider this a good trade. Mercantilism has it's uses, but even if you close your borders, inflicting significant damage on the other civ's economy isn't one of them. I regard the diplomatic damage as outweighing the trivial amount of cpt AI 1 removes from the AI 2.

Yes there are circumstances where it is clearly correct for AI 1 to close borders, for example if there is only one other civ, or all other civs are at war with each other. I just don't think you can label an AI as always wrong for making the decision to retain open borders in a normal game. It is not "vital" to close borders under Mercantilism; it is highly debatable. As I've said this is just the kind of AI tweak which I can see as causing an AI to mess itself up (think, does Tokuwaga ever do well?)

 

[SPQR300]

Signing open borders with everyone not only results in better relations with the rival civ, but it results "you have traded with our enemies" negative relations with your rival's rivals, who are most probably your friends(and others too, on large maps you will get more negative relation points with other civs, then the positive relations you get with this civ). You should not aim to have good relations with everyone, cause you end up nobody being with you, and noone help you. I still think that relations with a rival don't really matter, getting friends is what really matters. You have to choose friends, try to form a "block" and shouldn't really care with the others. On smaller maps having 1 friend is more then enough. So when not closing borders to a rival civ you give free money to him, and the diplamtic benefits are not so obviously positive either. On smaller maps, or in later stages of the game, when there aren't many significant civilizations left, denying that gold can hurt them really hard. (not to mention that the AI gets bonuses to research, I think +15% on monarch, so negating the same amount of trade-route gold from both of you still results more damage to the AI.)