Check out a map of the world's busiest shipping routes:
Notice something odd? The lines don't spread across the open ocean. They bunch up into the same few gaps over and over, like sand through the neck of an hourglass.
Those who control the chokepoints, control the world.
The world’s trade runs through a handful of gaps narrow enough to see across. Major geopolitical leverage as we’ve seen with the Strait of Hormuz and Bab Al Mandeb in the Red Sea.
Both the Iranians and Houthis used a naval chokepoint to great effect to force their geopolitical aims. But they’re not the only ones in history to do so.
Here’s what we’ll cover in this piece:
What makes a good chokepoint?
How does denial play a role?
What economics make a choke point geopolitically important?
What are critical chokepoints you aren’t hearing about? Are they at risk?
I think the more useful frame is structural.
Three variables determine whether a naval chokepoint is a busy shipping lane or a pressure point that reshapes the international order, and they flow into each other.
The bottom of this article could be cut off in some email clients. Read the full article, unbroken here.
1. Geometry Is Destiny
A naval chokepoint starts with a physical fact: a narrow passage connecting two larger bodies of water, where traffic funnels through because there is no other option.
This is the baseline. You need a geographic feature that compresses movement into a single corridor:
A strait between two landmasses.
A canal cut through an isthmus.
A narrow and winding naval passage
The feature forces traffic, whether commercial ships, military convoys, or civilian vehicles, into a concentrated path where it can be observed, taxed, or blocked.
That’s all well and good, but what actually makes them threatening? Surely, no one threatens to close any narrow corridor at random. And that’s true.
I find two major factors determine how much leverage the compression creates. That’s largely how you assess its value.
What’s the cost?
The first is bypass cost. This is the single biggest factor between a chokepoint that inconveniences people and one that coerces them.
If an alternative route exists and is merely slower or more expensive, the chokepoint has limited power, because users can route around it when the cost of compliance exceeds the cost of detour.
If the bypass increases:
orders of magnitude more in time, fuel, or risk
no bypass exists at all
The chokepoint becomes structurally coercive. Traffic transiting has no viable option except to pass through and accept whatever terms the controller sets.
The range is wide. As we can see here:
You really have two bypass costs is affected by two main factors:
Rerouting cost. That’s expensive and slow, but shipping companies can absorb it, and many did for two years after the Houthi attacks disrupted the Red Sea approach. Alternatives existed, like the Cape of Good Hope, which increased costs, but had a bypass.
Alternative routes. Like we are seeing in the Strait of Hormuz. There’s no maritime alternative at all, because the strait is the only exit from the Persian Gulf. There is no long way around. The bypass cost is very high. And it starts to affect markets and commodities.
Rerouting a tanker around Africa instead of through the Suez Canal adds 3,000 to 6,000 nautical miles, 10 to 15 extra days, and $1.55 to $3.07 per barrel in fuel costs.
And this was the effect:
The general rule:
the less it costs to go around a chokepoint= less leverage the chokepoint
more it costs to bypass = greater leverage and coercion strength
If it is impossible to bypass it, then the cost of bypass gets higher. If the options are lower, it means its harder to increase the political leverage of a single chokepoint.
For example, South Asia has multiple potential bypasses:
But that’s not as important as who’s nearby. And that makes a massive difference.
Who’s nearby matters too.
The second factor is who flanks the passage. A chokepoint is a physical feature. But its strategic character depends on the political identity of the states sitting on its edges.
![R] "Tsushima","Kagero" Bitwa Pod Cuszimą 1905 - strona japońska cz.2 - Forum Modelarzy Kartonowych PaperModels.pl](https://substackcdn.com/image/fetch/$s_!Dt4-!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F5a8e144d-b51c-43eb-847e-bbca388f178f_1280x903.png "R] \"Tsushima\",\"Kagero\" Bitwa Pod Cuszimą 1905 - strona japońska cz.2 - Forum Modelarzy Kartonowych PaperModels.pl")
A strait bordered by two friendly or neutral states functions as useful infrastructure, and nobody spends time worrying about the Strait of Dover. Chokepoints like this:
Malacca
Tsushima Straits
Panama Canal
These seldom make the news. Powers on both sides of the chokepoint or passage have no reason to close or restrict it. So, while its strategic geographic importance remains, its political one remains small.
Want more in-depth analysis? Get members-only content for the price of a small coffee per month:
Full-length articles and deep dives
Members-only analysis and How to Learn Strategy.
The entire archive of great politics, power, and strategy thought.
But that changes massively a strait with on one shore you have a state with:
revisionist geopolitical interests
territorial grievances
the capacity for asymmetric aggression
That transforms into a different category of problem and makes any naval choke point into a potential flashpoint.
Iran is a great example of this in news, as I mentioned before in the 1000 Year Chokepoint. But they arent the only ones, and the Houthis are a great example:
These seem really mundane, but control of one side can compel extreme actions. Geographic compression, bypass cost, and the identity of flanking powers together set the physical baseline.
They determine whether a chokepoint exists and how hard it is to avoid. The next question is whether anyone can weaponize it.
2. Denial Over Defense
This is the military variable. Its a tricky one too.
People ask if a chokepoint can be defended, but realistically it doesn’t matter if they can defend it. It matters more if they can deny it. These are different things.
Iran is not physically using its navy to hold the Strait of Hormuz. Nor is the People’s Liberation Army Navy permanently station ships in the strait. The reality is about flow.
Chokepoints are nodes in the governance infrastructure of a world order. Its why so many world empires from Britian to Imperial Japan try to control them.
But that’s the source of the first question:
Who can come and who can go?
Defending a chokepoint means holding it open for your own traffic, while closing it to adversaries. That requires sustained naval or ground superiority in the area.
The UK did this with Gibraltar:
What this means is that denying a chokepoint is raising the cost of transit above what commercial or military traffic will tolerate
You don’t need to control the passage. You need to make using it painful enough that ships, trucks, or aircraft reroute, insure at higher premiums, or stop transiting altogether. And there’s two a[ppoaches to do it.
This distinction matters because denial is accessible to actors who could never achieve defense. And small nations can do this too.
Small nations deny by raising asymmetric cost
A regional power, or even a non-state militia, can deny a chokepoint with asymmetric tools that cost a fraction of what a blue-water navy costs:
The Houthi movement proved this at the Bab el-Mandeb, the 16-mile-wide strait connecting the Red Sea to the Gulf of Aden and serving as the southern gateway to the Suez Canal. Iran is proving this in the Strait of Hormuz.
Even when attacks stop, traffic does not recover quickly. In the Houthi’s case, shipping companies were still routing around Africa. Carriers, insurers, and route planners had rebuilt their operations around the assumption that the corridor could not be trusted.
In the Strait of Hormuz, we still see a very low number of transits compared to pre war:
The cost asymmetry made the campaign sustainable: a multi-million-dollar naval interceptor to destroy a drone costing a few thousand dollars. The attacker replenishes faster than the defender and can sustain the campaign longer.
The Houthis operated from one of the poorest countries on Earth and imposed costs on a canal that generates $9.4 billion in annual revenue.
Certain physical conditions favor denial over defense:
Shallow water limits submarine maneuver and keeps conflict close to shore, where the coastal power has the advantage.
Narrow width compresses the engagement zone, which means a technologically superior navy operating from thousands of miles away cannot spread out and use its reach advantage.
Shore-based missiles, fast-attack boats, and naval mines exploit both conditions.
These are the tools of the coastal defender, and they are far cheaper. If a nation with such cost asymmetry can lock a choke point? Then its different with a great power.
Large nations do it on multiple levels
Great powers raise the cost and physically remove the option.
Their denial is not only probability game of sporadic hits that shift insurance premiums. But its capacity to declare a chokepoint a kill and danger zone and make it stick.
Everything up to now has been about raising the price of passage until ships reroute or pay more to insure the risk.
A great power can rely on sheer force. It can take the approaches to a strait into a danger zone and hold it that way for as long as it wants. Nor does it need to be physically present in a naval choke point itself.
Nothing crosses, military or civilian, until the great power decides otherwise.
How? By stacking layer on layer until no safe path is left. This is called layered defense, and it gives a great power advantages:
Space-based surveillance and targeting provide persistent, all-weather tracking of every contact in and approaching the chokepoint. Nothing transits unseen.
Over-the-horizon radar networks on land or mobile platforms fuse with satellite constellations to cue long-range precision fires the moment a vessel enters the engagement basket.
Long-range anti-ship ballistic missiles (e.g., DF-21D, DF-26) and hypersonic cruise missiles compress the timeline from detection to impact to minutes, making defensive interception geometrically harder than in the asymmetric case.
Submarines operating in the deep approaches and shallow chokepoint itself add a silent, undetectable denial layer that can sink high-value escorts or seal the passage with torpedo and missile ambushes, even after surface and air defences have been suppressed.
Strategic bombers and land-based strike aircraft flying from dispersed bases can saturate a chokepoint with massed volleys of anti-ship missiles, overwhelming any conceivable fleet air defence.
Advanced mining moves from static moored mines to programmable, influence-fused, and mobile mines that can be seeded covertly by submarines and discriminate targets, making sweeping a protracted, high-casualty operation rather than a clearance task.
This can be run at multiple levels to. So hard denial by a large nation raises the escalation and the threat vectors dramatically.
So there’s more than one way to seal the door. A great power runs all of it as one machine. Layered defense is no joke.
But navies are expensive to maintain, and being able to project and sustain naval power is expensive. Hard power isn’t always an option.
But if they’re not willing to use hard power, how else do great nations maintain hold?
Denial by Treaty
There’s a second way to deny a strait, and it fires no shots. Great powers and large nations simply use their diplomatic weight.
The law of the sea was built to keep straits open. Its core rule is simple: a country can’t bar the ships of the world from a passage everyone depends on.
So how do you deny a strait using law that was written to keep it open?
You carve out at an exception, by defining the rules of passage. There’s several, like the Suez and Panama Canals. But the best good example is the Bosphorus.
Picture the only door to the Black Sea: one narrow channel, the Bosporus, threading straight through the middle of Istanbul. Whoever holds that channel holds the sole passage between the Mediterranean and the Black Sea.
Turkey holds it. And in 1936, Turkey got the world to sign its terms.
The Montreux Convention lets Ankara:
Ban foreign aircraft carriers from the Black Sea
Cap how much foreign warship tonnage can enter
Limit how long those warships can stay
So the strongest navies are careful about entering the Black Sea.
Why would a superpower obey a piece of paper? International law has no binding affect, nor has a military to enforce it.
Because the paper was never the thing stopping them. The other great powers are. Break the treaty and you win no battle. You turn yourself into the country that breaks its word, with every other signatory now lined up against you. To most powers (most of the time) the political costs didn’t match.
But a treaty holds only while the strong want it to hold.
When the Soviets wanted carriers in the Black Sea, they didn’t tear up Montreux. They relabeled their carriers “aircraft-carrying cruisers,” a category the drafters never imagined, and sailed them straight through:
The rule sat untouched on paper, and the Soviets found a legalistic solution. But the world went along with it, since they couldn’t force to USSR to do otherwise.
That’s denial by treaty. It costs almost nothing to hold, and it works right up until the balance of power underneath it shifts.
3. The Inelasticity Premium
The geographic and military variables determine whether a chokepoint can be weaponized. The economic variable determines how much damage that weaponization inflicts.
It’s a concept you might have heard before in high school or college: demand elasticity.
Basically, can you replace goods. Then if those goods can be substituted, stored, or sourced from elsewhere when a supply route is cut.
Closure of a chokepoint carrying these goods creates logistical disruption:
delays,
rerouting costs,
inventory drawdowns.
price spikes visible in futures markets within hours
consumer price increases within weeks
Painful, but manageable.
Other goods have steep, short-term inelastic demand.
Consumers and industries can’t quickly cut back, and they can’t switch to alternatives when supply is cut. Closing a chokepoint that carries them creates an immediate economic shock:
price spikes in futures markets within hours
consumer price increases within weeks
political consequences within months
That second kind is where a chokepoint earns its premium: the extra damage it inflicts for one reason only, that its cargo is the kind nobody can live without.
If you have inelastic demand for commodities to critical industries going through a strait, it increases the leverage.
Oil is the textbook case:
Power plants, refineries, the engine in your car: none can switch fuels in a hurry. So when a fifth of the world’s oil suddenly can’t move, demand has nowhere to go. People pay whatever it takes.
So what makes a strait economically dangerous? Three things stack up:
how much moves through it
how stiff the demand is for its cargo
how fast the pain spreads when it stops
Run all three high, and closing the strait shakes the world economy. With the right political alliances, credibility, and leverage, it can be a very effective deterrence:
Which is why the smart countries build a back door before they need one. A second route is really just a way to make your own demand less stiff, to give yourself somewhere else to turn.
During the late 1970s and the subsequent Tanker War (1984–1988), Saudi Arabia recognized its vulnerability to a Persian Gulf blockade. They built the East-West Crude Oil Pipeline a massive 745-mile steel artery capable of pumping crude from the Eastern Province fields directly to the port of Yanbu on the Red Sea.
While it hasn’t totally gotten around Hormuz, it has allowed Saudi to do some risk reduction. But it cannot handle the shortfall in tankers.
That’s the strategy around naval chokepoints. Build the detour or find alternate transit paths before the gap closes. You can buy time to handle the shock. Or at least mitigate it.
Wait, and you pay full price at the worst possible time.
But if Hormuz is in trouble, what is other chokepoints that are geopolitical risks?
4. Chokepoints not in the news.
Let’s look at a few well-known choke points. There’s many, so let’s talk about five critical ones.
I’m going to skip Hormuz, since I’ve talked about its 1000-year advantage in depth previously. And I’m sure you’ve heard too much about it already.
Let’s talk about the risks for some other ones:
1. Malacca
For six hundred years it was the prize of the East.
The Sultanate of Malacca grew rich taxing the ships that had no choice but to pass.
Control then fractured: the Portuguese stormed the port, the exiled royals founded Johor to fight them, the Dutch seized it next, and finally the British united Penang, Malacca, and Singapore to command the entire passage.
So, like Hormuz, still holds huge strategic value.
Today three countries share its banks. Indonesia to the south, Malaysia along the peninsula, Singapore wedged into the pinch point.
The last time the neighbors truly fought over this region was Konfrontasi in the 1960s, when Sukarno’s Indonesia tried to strangle the newborn state of Malaysia.
Run it through the four factors, and Malacca is the mirror image of Taiwan. Huge on paper, light where it counts.
Width: small. At its tightest the strait pinches to 1.7 miles, narrower than almost any gate on Earth. A single grounded ship can back up the traffic of a continent.
Firepower: low. Here’s the catch. No hostile power sits on both shores. Indonesia, Malaysia, and Singapore share the water, and none of them wants it shut. There’s no hand hovering over the valve.
Cargo: enormous. Close to a third of all world trade funnels through here, and roughly 80% of the oil China imports. If this gap were a country, its throughput would rank among the biggest economies on the planet.
The actor: diffuse. The danger isn’t a state with a grudge. It’s pirates, accidents, and congestion, a hundred small hazards instead of one big menace. Nobody can credibly threaten to close it, so nobody collects the rent.
So the busiest chokepoint on Earth carries almost no leverage. Geography and cargo are maxed out, but leverage needs a motivated actor who can slam the gate. Malacca doesn’t have one.
Low across all four.
2. Bab el-Mandeb
Bab el-Mandeb was the southern door to antiquity’s richest trade lane—incense, spices, and silk passed here between the Mediterranean and the Indian Ocean for millennia.
Its strategic value made the surrounding coasts a prize for the Ottomans, the British (via Aden), and later Cold War patrons.
Controlling this gate meant controlling access to Suez and the Red Sea. Like in Malacca, piracy has also remained a problem due to its narrowness.
If we take the four factors:
moderate width (roughly 16 miles at the narrowest, with Perim Island splitting the strait),
proven military deniability (the Houthis demonstrated sustained denial for two years using cheap anti-ship missiles, drones, and naval mines),
high economic cargo as the southern gateway to Suez—about 15% of global trade transits here, including a huge share of Europe–Asia container traffic and Gulf energy exports,
a non-state threatener whose success has reshaped how defense planners worldwide think about asymmetric A2/AD.
Bab el-Mandeb’s weight comes from a non-state actor proving that a narrow waterway no longer requires a rival navy to close—it only requires low-cost stand-off weapons and the will to use them.
High across all four.
3. The Taiwan Strait
The Taiwan Strait is a fault line four centuries old.
It has always been a seam between rivals. Dutch traders held it, then Ming loyalists under Koxinga, then the Qing empire, then imperial Japan, and finally the Nationalists who fled across it in 1949 and never came back.
For most of that history, holding the strait meant guarding the Chinese coast. Now it means more. The prize isn’t the water. It’s the island on the far side, and what that island builds.
Run it through the four factors, and Taiwan looks moderate on paper and frightening underneath.
Width: moderate. Roughly 80 miles at its narrowest, broader than any other gate on this list. But it’s packed. Nearly half the world’s container ships thread it, and about 88% of the largest vessels by tonnage.
Firepower: high. China has the tools to choke it. Anti-ship ballistic missiles that reach clear across the water, a navy that can throw up a blockade, and enough air power to own the sky above.
Cargo: off the charts. Ordinary containers, plus the one thing no other chokepoint carries. Taiwan’s TSMC builds over 90% of the world’s most advanced chips, the silicon inside your phone, every data center, every AI system, every guided missile.
The actor: motivated, and open about it. China calls taking the island a core national goal. That turns closure from a hypothetical into a scenario every serious war plan already runs.
Taiwan draws fewer headlines than Hormuz. It may matter more if China decides to forcibly reunify, or the ROC declares itself an independent state.
Medium across all four. But medium here holds the whole digital economy hostage.
Medium across all four.
4. Gibraltar
Gibraltar was the pillar of Hercules that the Mediterranean world could never ignore.
Under the Moors, then Castile, and later as a British fortress after 1704, it was a gate that could be slammed shut. Control of the Rock meant the ability to bottle up or release the entire Mediterranean fleet.
Its so strategically critical that Admiral Nelson fought a decisive battle nearby that assured the British Empire’s naval dominance for the next 100 years:
If we take the four factors:
moderate compression (8 miles at the narrowest, but highly channeled by physical geography),
low military deniability today—one shore is a British Overseas Territory (NATO ally), the other is Spain (NATO/EU), and the southern shore is Morocco (a stable, Western-aligned state). No hostile power could realistically close the strait unilaterally,
moderate economic cargo—significant energy and container traffic between the Atlantic and the Mediterranean, and a crucial trans-shipment hub at Algeciras, but far less than Malacca or Hormuz in global share,
low threat profile—no state or non-state actor currently contests Gibraltar’s freedom of navigation; the disputes are political (Brexit, sovereignty) not military.
Gibraltar’s risk in the modern era is almost entirely below the waterline: critical undersea data cables and gas pipelines that funnel energy and digital connectivity between Africa, Europe, and beyond. Sabotage there would be the new kind of choke, and it would be silent.
Low across all four.
4. Tsushima Straits
Tsushima was the scene of Japan’s most mythologized naval victory in 1905, when Admiral Togo annihilated the Russian Baltic Fleet trying to transit from Europe to Vladivostok.
It’s been an invasion highway for centuries. The Mongols crossed here, Hideyoshi’s armies launched toward Korea in the 1590s. Admiral Yi Sunshin’s domination of the islands on the Korean side ended the Japanese invasion.
Control of these straits meant control of the gateway to the Sea of Japan and the maritime approaches to the Korean Peninsula and the Japanese home islands. It also critical for resupply and trade between Japan and Korea.
If we take the four factors:
moderate compression. The strait splits around Tsushima Island, with the narrowest navigable channels around 30–40 miles wide but channeled by coastlines and shallow seas.
low military deniability. Both shores are held by U.S. treaty allies (Japan and South Korea). Combined naval and air presence makes sustained closure by any adversary extremely unlikely without a full-scale war. And even then, they would need to control the port of Busan and the southern shore. Something the DPRK tried during the Korean War.
high economic cargo. This is the energy aorta for Japan and South Korea, carrying a massive share of their oil, LNG, and containerized trade from the Middle East and Southeast Asia. There’re also significant volumes for China and Russia’s Far East. Busan is a major port involved in shipbuilding and cargo.
low threat profile. The only plausible disruptor is North Korea, whose submarine and mine capabilities could harass but cannot close the strait in any durable way against allied dominance.
Tsushima’s weight comes from the sheer volume of energy and trade funneling past a single chokepoint. But the alignment of both littoral states within the U.S. security umbrella keeps the practical closure risk low.
Low across all four.
Takeaways
Five patterns repeat across the entire timeline:
Geometry is just the door. Bypass cost is the lock.
If you can sail around, the chokepoint has no power. If you can’t, the chokepoint’s leverage gets magnifiedThe most dangerous chokepoint isn’t the busiest one. Just because the world depends on a strait doesn’t mean its at risk, unless the geopolitical actors around it contest it. Even then, it depends on their ability to do it.
Economics matter. Inelastic demand raises the geopolitical leverage from a choke point. If you have inelastic demand for commodities to critical industries going through a strait, it increases the leverage.
Denial beats defense every time. Holding the water is a nice-to-have. The real ability is can you make passing through expensive enough that nobody risks it. Even smaller powers can do this.
Treaties can limit a chokepoint. If a strait is free passage by norm, then this doesn’t apply. But a treaty can limit what sort of ships can transit the strait. Which affects military power projection.
As always politics matters.
Who borders a strait determines if it’s even a flash point. Their incentives to block it also matter.
So just because a strait is narrow and high traffic, doesn’t mean it will be a naval choke point that affects geopolitics.
Thanks for reading!
As always, thank you, paid subscribers, for supporting The People’s Art of War.
Before then, if you have any questions or comments, feel free to comment. I’ll answer them in a follow up podcast or article.
And if you haven’t already followed:
Spotify: Statescraft
YouTube: People’s Art of War
long but very insightful. thank you.