Choke Points

Have you ever driven through a canyon and thought to yourself, "man I hope no one primed these canyon walls to blow and cause a landslide." as you went through?  If you have, you identified a natural choke point.  The intersection of roads, trails, and paths are natural choke points.  Canyons, bridges, are choke points (sometimes referred to as canalizing terrain). 

Examples of a cut and fill, note potential for explosive initiated landslide

It is common wisdom that choke points are a good spot to set up an ambush.  The reasoning is that the terrain naturally inhibits the enemies freedom of movement without significantly hindering your own.  This means the enemy has to stay in the kill zone longer.

Choke points are also a good place to set up checkpoints, roadblocks, and other "movement control" operations.  Whether checking for papers, overweight vehicles, contraband, or persons of interest, the basic principle is the same.  Set up an overwatch position on the choke point, set up the movement control station, and get down to business. We will come back to this aspect of choke points in a bit.

How do you choose a choke point to set up an ambush?  If you were a combat arms NCO E5 or E6, right now you are thinking, "Well the commander tells me where to go, what to do, and when to do it, so I really don't know how to pick a good area to set up an ambush."   If you were a Military Intelligence NCO, you say, "Well, I don't really pick the spot, but I nominate it based on the tools of predictive analysis to increase the likelihood of mission success."  If you were an E7 Combat Arms NCO you probably have a damn good idea where to set up a platoon level ambush and helped develop new Lieutenants so they could too.

If you were a Company Commander, you probably didn't get much love from the S2 in planning company mission priorities, so you had to put together your own team of smart guys (I've met more guys eligible for MENSA in the Infantry than in MI) and they start looking at things going on in your area.  Most of the time they get a week or two week class on how to use time wheels, pattern analysis tools.  This training helps, but in the end having a smart person look at a problem, look at data, and they will normally figure something out.

The cycle usually goes something like this:  The enemy does something twice in your area, the smart guys work through details trying to answer the question "how" the enemy did what they did.  This creates a list of infiltration and exfiltration routes.  The routes are compared against other known enemy locations and units.  The routes are prioritized and assets are assigned to watch them.  Once the enemy triggers an asset (could be anything from a security camera to a scout team) the ambush team gets the mission to go to the spot on the map where the Commander wants the enemy killed.

Chock points can isolate a town or city

That sums up a Company level targeting cycle.  Identify an enemy formation.  Identify likely places where that formation will be.  Allocate an asset to detect that enemy.  Allocate firepower to destroy the enemy.  The detection asset triggers the firepower asset.  Filling in the details for each stage of the cycle gives you the idea of how much work needs to be done to give a combat arms NCO the "do this, here, at this time" type order.

On the other side of the equation, choke points can be used to isolate.  The Torkhum Gate on the Afghan/Pakistan border is a good example of key economic terrain.  Shutting down that port of entry grinds the delivery of goods to a halt for a large chunk of real estate.

What follows is not a game plan, this is not advocacy for violence.  None of this information is classified, and you could plan this with a Rand McNally state map.  This is why security professionals tell you that you can't protect everywhere, all the time.  Think about the US state of Washington as a mental experiment in using choke points to isolate a population.  Say that the Communist Revolution Of The Common Humanity (CROTCH) took place in the Olympia Tacoma Seattle (OTS) area, the rebels managed to sabotage all the military assets not deployed from Joint Base Lewis McChord, and the communist scum were supported by sympathetic suppliers in Oregon and Colorado.  A month after the revolution anyone who wanted to leave the OTS area is gone and JBLM is being resupplied via air, but the post lacks the ability to project power without reinforcements.

How would you isolate the CROTCH from support? The southern border is mostly the Columbia river.  The Cascade mountain range cuts the state in half, and the northern border is Canada.  If you wanted to isolate OTS the easiest way to do it is to blow up bridges (I-5, (-205, US 87, and US 101) crossing the Columbia from Oregon, and blow up bridges and cause landslides on the freeway and highways that cross the Cascade range (I-90, US 14, US 2 and US 12).  This would force truck traffic to have to go all the way into Canada.  Blowing a few bridges on I-5 north of Seattle would frustrate that route as well.  Around 30 explosive devices to bring a big chunk of real estate into economic isolation.  Now OTS forces are cut off from their base of support.  The sea port remains open, but a naval blockade along the Straights of Juan de Fuca stop support coming in that way, and the airport is functionally grounded due to air superiority.

Choke points can isolate a region

If you do this, the CROTCH is in a world of hurt. 

If you want to isolate a smaller geographic area, all you have to do is identify the choke points going to and from that area, then deny them. The enemy or civil populace will react and start using low volume "rat lines" to move personnel, equipment, and food.  Rat lines are a good place to conduct ambush operations.  The only difference between a Company level operation and a Campaign level operation here is scale.  An attack is an attack is an attack (although the bigger the organization the more things you have to deconflict, so while the principle is the same the execution can be vastly different).

Conversely, if you want to "get there from here" you need to identify choke points in advance, send out advance forces to secure them (this is the role of scouts), and make sure you deny the enemy a terrain advantage over you.  This is how a large ground force invades, why every Airborne brigade has "airfield seizure" as a mission essential task, why our Engineers have bridging capabilities, and why our logisticians get to dictate the pace of movement more often than not. 

Some products are easier to disrupt using choke points than others, even on a worldwide distribution network.

So, how do you defeat an enemy that is isolating you using check points?  The best way is to cache what you need on the other side of the choke point before the enemy occupies.  Anytime you can travel light, without looking like a target, you should take that option.  The terrorist organizations in Afghanistan are pretty good at this, of course they've been setting up cache's for this purpose since the 80s.  Other methods include bribing your way through a checkpoint, smuggling items in multiple parts and assembling them later, or figuring out how to capture the material you need from the enemy closer to your objective.  Your imagination is the only limiting factor when it comes to trying to solve this problem, or use the data set to frustrate your enemy.