Thank you for the quick responses! So if I understand this correctly, the AI (including barbarians) is encouraged to build economically completely senseless cities due to military considerations. If there is a city, there will be city defenders - and the chokepoint is held. Bonus points for hindering foreign troops to pass when no open borders exist. At least I think I understand the reasoning now. I admire the idea as such, but... Unfortunately the Ai often destroys much better city positions a few tiles before such a chokepoint. And I have seen civs build their second city there, even though there was an abundance of much better city sites (economically). I doubt that the setback of wasting your second city (or your third, or your fourth) for a completely unproductive site is worth the military bonus. And it is a setback: You pay higher maintainance for the city plus guards and delay the founding of a productive city with all the boni that entails. Like higher research which allows you to build better defenders to actually defend a chokepoint. In a recent game I have seen the Ljosalfar take such a chokepoint city from the Sidar very early. I only saw Ljosalfar scouts. The advantage of holding such a chokepoint is undeniable. There are three general possibilities: City, fort, nothing other than naked terrain modifiers (preferably within borders). I would go with a fort or with the naked terrain modifiers. The latter is actually even better than a fort, at least for a while - if you have to remove a forest to build the fort. In my estimation forts are not later available than when it would not hurt you overly much economically to waste a settler and money for increased city maintainance. And I love the super forts which you can even build outside your territory - the perfect solution for this situation. Do I guess correctly when I guess that it would be really a lot of effort to implement a more direct "hold the chokepoint" behaviour (i.e. with troops in forts) than to simply raise the AI's urge to build winter sport resorts in tight mountain passes? However you answer that question, I would say that the added value for city site selection for chokepoints is definitely too high.