Defense Strategies

October 4, 2010 11:10 PM

Is it better to build a fort/castle on a plain or on top of mountain?

Is there any paper/link which gives the role of the topography of the land while building a defensive structure - Fort/Castle.

Question arose while playing Starcraft 2. I was on top of a hill and had setup an extremely good defense network. Resources ran out. Enemy was out of range and just waiting building a huge army at the base where they had access to resources, they just sent in small forces at a time. Since resources ran out, was forced to get out to the plains through 2 routes where the enemy ambushed me :( .

While logic dictates that height is an advantage ( increased range, better defense etc ), what if the enemy just waits for you to run out of resources. Is it easier to maintain a siege of a fort on a moutain as it has limited routes?

posted by manny_calavera to Society & Culture (16 answers total)

Where might potential enemies come from? Is your mountain fortress at the highest point? Is it positioned in front of a pass (such that it has blocked the only way through the mountain, and can be attacked from one side or the other, but never from both sides by the same enemy)? Is your fortress on a plain by a river? How big is it? Does it have a moat? Is it easy to surround? At both fortresses, have you made sure that you have a supply of water (most important) and food (less important, but still crucial) that can outlast whatever siege your enemy can mount?

My point is this: neither is better. What matters is the specific characteristics of the land, and how well you've prepared.
posted by ocherdraco at 11:16 PM on October 4, 2010 [1 favorite]

Well there's Clausewitz on fortification, for a start. For your purposes:

11. For the defence of rivers and mountains. Nowhere can a fortress answer so many purposes, undertake to play so many parts, as when it is situated on a great river. It secures the passage at any time at that spot, and hinders that of the enemy for several miles each way, it commands the use of the river for commercial purposes, receives all ships within its walls, blocks bridges and roads, and helps the indirect defence of the river, that is, the defence by a position on the enemy's side. It is evident that, by its influence in so many ways, it very greatly facilitates the defence of the river, and may be regarded as an essential part of that defence.

Fortresses in mountains are important in a similar manner. They there form the knots of whole systems of roads, which have their commencement and termination at that spot; they thus command the whole country which is traversed by these roads, and they may be regarded as the true buttresses of the whole defensive system.

However, please note the linked translation is obsolete. Grab a more updated translation from your library.
posted by Fiasco da Gama at 11:22 PM on October 4, 2010

[ahem] on fortification.
posted by Fiasco da Gama at 11:23 PM on October 4, 2010

I remember reading that most sieges in the Middle Ages lasted as long as it took one side to starve. Few were actually resolved by breaching the walls and storming the castle, which was hard work and likely to be suicidal if the fortress was properly manned. Mountaintops are easier to defend but harder to supply, as you discovered. But more importantly, there aren't a lot of mountaintops that are along crucial trade routes or large centers of population. It's not just a question of supplying the fortress during war, there's supporting itself during peacetime as well. I suspect this tended to locate fortresses less than ideally from a purely tactical standpoint.
posted by fatbird at 11:27 PM on October 4, 2010

Also, don't feel bad about being defeated in a siege of a remote hard-to-supply outpost. Better planners than you have got it much more wrong.
posted by Fiasco da Gama at 11:35 PM on October 4, 2010 [1 favorite]

It's a complicated one. It depends what you're defending, who you're defending it from, and what resources are available on both sides of the siege.

Fortified settlements are/were built for more than just defence, in places that had topographical value beyond siege resistance, so there'd always be compromises: for instance, building high on a river bend, like Durham or Richmond, would offer protection in Clausewitzian fashion, but also give a besieging enemy access to a good supply network.

Anyway, something like Gravett's Medieval siege warfare is a decent place to start for your classic Castle vs. Trebuchet contest, but fortification and sieges are old-school warfare. (Sun Tzu hated sieges.)
posted by holgate at 11:43 PM on October 4, 2010

The most important thing was having a secure water supply. When a fort was placed next to a river, and set up so that the defenders could reach the river to get drinking water, the fort would be much more secure.

Placing a castle on a hill was quite common, but then they had to worry about the water supply. If a well was possible, that was good enough. If not, some such castles included rather extensive cisterns.

One of the earliest predecessors to the fully mature castle was known as a "motte and bailey fortification". The motte was on a hill.

I don't know that you'd want to put the castle on top of a mountain as such (as opposed to a hill) because it would vastly increase the expense and difficulty of building it, without really making it any more secure in any obvious way.

As to the Clausewitz quote, keep in mind that he did his writing in the 1820's, long after the development of cannon. Classic castles became obsolete once cannon became common because their walls were easy to knock down. The new kind of fortification developed in response was known as a "star fortress" and it wasn't practical to build them in the mountains. They pretty much had to be built on a river, because moats were the primary defense. (Here's one I personally have visited. It was fascinating to walk around the entire periphery of it, to see all the works.

What Clausewitz is talking about isn't the kind of castle you're thinking of. He was referring more to what we'd call a "military base".
posted by Chocolate Pickle at 11:57 PM on October 4, 2010

The castle in Bratislava kind of has both of these advantages. It's on a fairly commanding hilltop above the Danube, and the surrounding country is fairly flat in both directions towards Vienna and Hungary. And it's apparently been used as a fortress for many thousands of years, because it's in such an awesome strategic position.
posted by Cimrmanova at 12:45 AM on October 5, 2010

I think the main problem you had there was the lack of resources, not positioning. Height is an advantage (especially since in Starcraft II you can fire down but not up) but having sufficient resources is the killer there... I mean, imagine you had built a really good defense network on flat ground, but had no resources because your enemy had you surrounded. You'd still lose.
posted by Xany at 1:19 AM on October 5, 2010

Militarily, castles are about delay, prevention, and control. You need all three to make'm work.

The resources held in a castle determine how long it will delay. Will the water last until the Vikings get bored and go off for easier prey? Will the food last until the army can show up and deal with the Welsh rebels? Surely the Roman army has to get bored standing around Masada at some point, right?

The castle's defenses, its walls and moats and siege tanks, determine how long it will prevent the attacker from taking the castle. Until the cannon, thick stone walls were pretty much the height of technology, then came the star forts with their earthworks, moats, and covering fire.

Finally, castles allow the defender to control a larger area than might be possible with just the troops/resources on hand in the castle itself. Castles along the German rivers let their occupants charge tolls, star forts extended control of a harbor, and so on.

So you Starcraft II 'castle' probably had great defenses. It probably allowed you to control what went on near the 'walls' no problem. But it lacked for resources - you couldn't replace what you lost or used once they ran out. Given the scenario for most SC matches is 'lets-you-and-him-fight' that meant that it wasn't really much of a castle at all, there was nothing you were achieving by delaying your foe. If you had to protect an artifact or hold out until a clock counted down, then your castle would have had a purpose. But without that element, it wasn't really a castle, more of an elaborate tomb.
posted by robocop is bleeding at 5:17 AM on October 5, 2010 [1 favorite]

I think the ultimate question is "What do you want to do with the plain and/or mountain?" Because if what you want to protect is on the plain, that's where you build your fort, even if another location would be more defensible.

In video games, the answer to that question is usually "Nothing in particular," though the Civilization franchise and certain other games with non-military victory conditions can make defense of particular geographical features worth defending realistically. But with StarCraft, WarCraft, basically all RTS games, the only victory condition is generally eliminating the other players, so fortifications, whose main purpose is making victory too costly to pursue, lose their main raison d’être.
posted by valkyryn at 5:50 AM on October 5, 2010

In the age of air superiority it doesn't matter. For ground attacks, tanks, artillery, and howitzers will still be able to decimate a mountain fortress although it will require infantry to take the fortress. It depends on what you need to defend against to determine the best defense.

I'm currently playing Warzone 2100 which is a good freeware version of Starcraft. The early missions start out defending against ground forces but then you have other missions in which you need to configure defenses differently.
posted by JJ86 at 6:27 AM on October 5, 2010

Came in to quote von Clausewitz. The destruction of the enemy's forces, and hence his will and ability to fight is always your goal. The placement of fortifications must be for that purpose. That's why they are generally built on routes--in order to prevent easy passage to an area where you may be destroyed, or to give your forces a chance to prepare for a battle they are likely to win. Thus is why they are placed in areas that the enemy must have if it is to win. Narrow defiles and canyons which lead to strategic areas, guarding fords and ferries, etc. Fortifications are expendable and should be treated as such. They must serve the ultimate purpose of destroying the enemy's forces.

Hence, site your forts where you can delay or trap the enemy due to terrain conditions, or where you can use them to defend a lot with a little where you need defense.
posted by Ironmouth at 7:17 AM on October 5, 2010

There is a saying among the military that amateurs study tactics (like fortress location) and professionals study logistics (how does your army get what it needs to survive and fight). This seems to be true across a wide range of human endauvor, not just war. Successful companies, families and countries all do this on different scales. On top of this there are two ways to wage a war, and they take a more strategic view of logistics. You can outmanuever your opponent-which takes superior training, superior manpower (not numbers-more capable people in the right positions), superior support networks (the usual meaning of logistics), but is really difficult. Germany in the Second world war maintained got the first two conditions right but not the third and lost to the side that good the third right but missed the first two (Soviet Union and USA). Getting suport networks right is easier than the first two and is called attrition warfare-you just last longer than the enemy. So the side that wins is usually the one that gets the third right and doesn't make too many mistakes about the first two conditions. And when you are talking about a war game scenario-always figure out what your victory conditions are and fight your game solely for those conditions, not proving your tactical genius. In the real world this is known as paying attention to politics.
posted by bartonlong at 10:03 AM on October 5, 2010

Your enemy knew his Sun Tzu: ""First learn to become invincible, then wait for yours enemy's moment of vulnerability."

That's really the secret to the art of war--your height advantage is an advantage only as long as your enemies are unable to exploit it. Had you an infinite stock of provisions, you probably would have prevailed. Since you didn't, your enemy was easily able to exploit that vulnerability, the lack of resources, and go after you.

But the tables could easily have been turned, with you having all the resources and him taking advantage! So "Is a plain or a mountain better?" really can't be answered definitively for all situations. It's a case-by-case issue.
posted by misha at 10:10 AM on October 5, 2010

Starcraft (like almost all RTS games) is primarily a game of economics, and only secondly a game of tactics. Once the game has progressed beyond the first rush, if you can maintain control over more resources than the enemy, you'll win 9 times out of 10. Likewise, if your enemy controls more resources than you, you'll lose 9 times out of 10. Aggressive expansion is almost always a better tactic than building a fortress -- you want to defend your main base just well enough to keep the enemy from smashing your important structures, while establishing secondary bases quickly on all the closest resource points. Defend these just well enough to make it a hassle for the enemy to take them, and then think of them as free income for as long as you've got them. Whenever you can afford it, try to establish another one.

To do this properly, you'll need to scout early and often. Send an SCV to scout as soon as you can spare one. Find the enemy's base ASAP, and send your first couple attack units to kill his SCVs if he looks vulnerable. Then scout two or three of the resource piles closest to the enemy base. Send throwaway units to watch over these, preferably where the enemy won't discover them. Expand this network throughout the game, so that you can see all of the resource points.

In the meantime, create secondary bases as outlined above, and pump out troops rather than filling your bases with defensive structures. Use these troops according to the same philosophy: attack and destroy the enemy's secondary bases as soon as (s)he tries to establish them, in order to disrupt their economics. If you can't smash the base itself, then kill the SCVs as often as you can. You can even take over those bases yourself if it's easy to do so, but don't spend too much on defending them. All you really need to do is stop the enemy from expanding. If they do manage to build a hardcore secondary base you can't break, fine -- let it be and concentrate on keeping them from getting a third one, etc, while you work on your fourth and fifth.

If you have two productive bases and the enemy has one, you'll have access to twice the troops during that time, making it even easier for you to keep harassing and harassing so that they can't get that second base. And if you can build a third base in the meantime, and a fourth, and a fifth... you can see how fast this strategy snowballs, if you do it right. That's why expanding and going on offense immediately is more than worth the slight vulnerability your base will have in the early game. If the enemy attacks with everything he has in that sole moment of weakness, you might lose... but if he doesn't, you'll own the rest of the game. Economic momentum is everything.
posted by vorfeed at 2:18 PM on October 5, 2010