AsiaPac Sea Lanes: The Traffic That Holds the Region Together

A data memo. How many ships, carrying what, through which strait, and for whom — for the nine economies that share this water.

1. The finding

Trade is usually counted in dollars. The thing that can be stopped is counted in ships.

On the measure below, the nine economies of the Asia-Pacific move roughly 3,900 bulk cargoes a month between them — oil, gas, coal, iron ore and grain. China takes about 1,700 of those. Australia sends about 1,000 out. Japan, Taiwan and the Philippines live almost entirely on what arrives. Indonesia and Australia live on what departs. Not one of them can feed, fuel or pay itself without the others, and every one of them sails the same water to do it.

That is the whole argument of this memo, and the rest of it is the evidence.

The intervals inside which a government must choose between rationing and capitulation. Set against them, no fleet has ever reopened a closed sea lane.

2. How these numbers are made

A tonnage is not a ship. To turn annual trade into traffic, each cargo is divided by a typical parcel size for that trade, then by twelve.

The distinction between crude and refined product matters more than it looks. An economy that refines at home takes its oil in a small number of very large tankers; an economy that has closed its refineries takes the same energy in three or four times as many smaller ones. China, Japan and Taiwan are in the first group. Australia, Indonesia, the Philippines, New Zealand and Sri Lanka are in the second.

Each section states what is sourced and what is not. China's crude, coal and iron ore are from the General Administration of Customs. Japanese and Taiwanese gas and coal are from trade statistics. Australian iron ore and LNG are from Australian sources. The remaining cargoes are tonnages implied by the earlier version of this chart, carried forward while a full customs-sourced dataset is assembled.

3. The lanes themselves

Chokepoint volumes from the United States Energy Information Administration and published maritime statistics

Traffic is only meaningful once it is attached to the water it crosses. Five passages carry almost all of it, and they are not interchangeable.

Malacca

The strait between Sumatra and the Malay Peninsula is the shortest route between the Indian Ocean and the Pacific, and the busiest oil chokepoint in the world after Hormuz. Something in the order of a fifth of global seaborne oil passes through it, along with the great majority of the crude and liquefied gas bound for China, Japan, South Korea and Taiwan. At its narrowest it is about 2.8 kilometres wide.

Roughly 80 per cent of Chinese crude transits Malacca. That single figure is the reason the strait has a name in Chinese strategic writing — Hu Jintao called it a dilemma in 2003 — and the reason two decades of pipelines, reserves and overland corridors have been built to reduce it, without reducing it much.

Lombok and Sunda

The two Indonesian alternatives are deeper and wider than Malacca, and they are also longer. A tanker routed through Lombok instead of Malacca adds roughly three days to a voyage from the Gulf to North Asia. Lombok is the route large ore carriers already use, because the deepest of them cannot transit Malacca fully laden, and it is the obvious diversion if Malacca closes.

It is a diversion, not a substitute. Three days each way on every cargo is a permanent reduction in effective fleet capacity, at a moment when the fleet is already short. And Lombok and Sunda are Indonesian internal waters, which means the diversion depends on the disposition of a country that would itself be under pressure from both sides.

The Taiwan Strait and the Bashi Channel

North of Malacca the traffic splits. Cargo for northern China, Korea and Japan runs either through the Taiwan Strait or east of Taiwan through the Bashi Channel, between Taiwan and the Philippines. A large share of the world's container traffic passes through the Taiwan Strait, and the Bashi Channel is the deep-water alternative and the principal route for vessels avoiding it.

These two are the reason a Taiwan contingency is not a Taiwan problem. Cargo bound for Japan, Korea and the Chinese mainland uses the same water. A conflict there does not need to touch a single Japanese or Korean vessel to stop Japanese and Korean cargo, because the underwriters withdraw from the area rather than from the flag.

Hormuz

Hormuz is not an Asia-Pacific strait, and it is on this list because Asia-Pacific cargo starts there. About a fifth of the world's oil and a comparable share of its liquefied gas leaves the Gulf through a passage two miles wide at its shipping lanes. About a third of Taiwan's liquefied natural gas is Qatari, which is to say it is Hormuz cargo, and the same is true of a substantial share of Japanese, Korean and Indian supply.

The events of 2026 are set out in the sections above. The relevant point here is structural: the region's energy security has a single point of failure that lies outside the region entirely, and no Asia-Pacific navy has any standing at it.

What this means when read together

The passages are shared. Australian iron ore for China, Qatari gas for Taiwan, Indonesian coal for the Philippines, Japanese and Korean crude, and the container traffic that carries the manufactured goods back the other way, all cross the same handful of narrows. There is no arrangement in which one participant's cargo is interrupted and the others continue.

That is the whole basis on which this memo says the exposure is mutual. It is not an argument about goodwill. It is a matter of where the water is narrow.

4. What the ships are carrying

Energy agencies, national ministries and contemporaneous reporting — see sources

A cargo count says how much traffic a blockade stops. It does not say how long the country behind the port can last. That depends on three things: how much of the nation’s energy arrives by sea, what that energy is used for, and how many days of it are held ashore.

Two of those three can be set out on one measure, applied the same way to every economy: what share of the electricity is generated from fuel that arrived by ship, and what share of the transport fuel arrived the same way. Read together they separate the region into two kinds of failure.

The first is the easiest to state. Singapore imports about 98 per cent of its energy. Taiwan about 97 per cent. Japan produces about 13 per cent of what it uses. South Korea reports 22 per cent, but that figure counts nuclear generation as domestic production; strip it out and Korea produces 4.6 per cent of its own energy. These are not economies with a shipping problem. They are economies that are a shipping arrangement.

Singapore, Taiwan, Japan, South Korea, the Philippines and Sri Lanka import the fuel that makes their electricity and the fuel that moves their freight. An interruption reaches the grid and the road at the same time. China, Indonesia, Australia, New Zealand and Papua New Guinea generate their power from their own resources and import what moves everything else, so their lights stay on while their distribution stops. Both are serious. They are not the same problem, and they do not have the same remedy.

One qualification on the arithmetic. Excluding nuclear from Korea’s self-sufficiency is a fair way of showing how thin the domestic base is, but it should not be read as meaning the reactors stop when the gas does. Uranium arrives by sea like everything else, and its fuel cycle is measured in months and years rather than days. In an interruption the reactors keep running and the gas plant does not, which is precisely why the 30 days of gas is the number that decides the outcome.

The binding constraint is the smallest tank, not the biggest

Taiwan is the clearest case, and it is instructive because the numbers look reassuring until they are read together. In 2024 the island generated 288 terawatt hours, of which 83.2 per cent came from fossil fuel — 42.4 per cent natural gas and 39.3 per cent coal — against 4.2 per cent nuclear and 11.6 per cent renewables. Its last nuclear reactor closed in 2025.

It holds roughly 140 to 146 days of crude oil. It holds eleven days of gas.

The oil cannot cover for the gas. Oil-fired plant is about 4.7 per cent of Taiwan’s installed capacity, so the large reserve sits behind generators that cannot carry the load. Coal inventories run about seven weeks. A country with 146 days of one fuel and eleven days of another does not have 146 days. It has eleven, and then it is rationing electricity into an economy whose principal export is semiconductors, a process that cannot be interrupted without scrapping the wafers in progress.

Nor is the gas arriving through one door. Taiwan runs three terminals — Yung-An at Kaohsiung, Taichung, and Guantang in Taoyuan, which opened recently. That is more redundancy than a year ago, and it is still a system that funnels through a small number of fixed sites which ships must reach through contested water. The loss of one terminal does not reduce supply proportionally; it removes a share of the capacity to receive supply, which no amount of cargo at sea can replace.

Gas is not stored in this region. It is delivered.

Japan holds an average of about nineteen days of liquefied natural gas in above-ground tanks. South Korea about thirty. Neither has meaningful underground storage, and neither has an international pipeline connection. Europe can draw on depleted gas fields and salt caverns holding months of supply, and can move gas across borders by pipe when one route fails. The Asia-Pacific cannot do either. Every molecule arrives by ship, is held in a tank at the port, and is burned within weeks.

That is a structural difference, not a policy failure, and it explains why the region’s energy security is really a shipping question. A European gas crisis is a price crisis. An Asian one is a scheduling crisis, and schedules are what a contested sea lane destroys first.

Australia fails the other way round

Australia is the exception on the chart and it matters that the exception is understood, because it is routinely used to argue that Australia is not exposed.

In aggregate Australia is an energy exporter with high self-sufficiency, and its electricity is generated from domestic coal and gas. An interruption to shipping does not turn the lights off. That much is true.

Its transport fuel is another matter: roughly 90 per cent imported, from refineries inside the theatre, with two refineries left from eight in 2005 and reserves reported at 22 days of diesel against a 90-day international obligation. So the failure is not the grid. It is everything the grid does not move.

Diesel runs the trucks that carry food from the ports and the processing plants to the supermarkets. It runs the harvesters and the headers, and the road trains that take grain to the silo. It runs the haul fleet at every mine, which is to say it runs the export income. It runs the freight rail and the coastal shipping. It runs the generators at the hospitals when the grid does go down for its own reasons.

Australia in a supply interruption would have power and no distribution. The lights would be on in a country whose shelves were emptying, and the fuel to fix that would be arriving on the same lanes that had stopped.

And the fuel is not the end of it

Fertiliser arrives by the same route. Australia imports the overwhelming majority of its urea, which is why the package announced in May 2026 was a Fuel and Fertiliser Security Facility. A fuel interruption in one season is a fuel interruption. A fertiliser interruption in one season is a smaller harvest in the next one, and the effect lands twelve months after the cause, when the cause has been forgotten.

5. How fast it happens

Energy agencies, national ministries and contemporaneous reporting — see sources

Fast enough that the question of who wins is never reached.

Eleven days of gas in Taiwan. Nineteen in Japan. Twenty-two days of diesel in Australia. Thirty in Korea. Those are the intervals inside which a government must choose between rationing and capitulation. Set against them, the instruments that would supposedly reopen a lane operate on a different clock entirely: a naval deployment takes weeks to position, a convoy system takes weeks more to organise, and commercial confidence — the thing that actually restarts traffic — took months to return in the Red Sea after the last attack, and had not fully returned a year later.

Two further things compress the intervals. Storage figures assume normal consumption, and consumption rises at the start of a crisis as industry and households front-run the shortage. And the figures are national totals that assume the fuel can be moved to where it is needed, which in Australia’s case requires the diesel that is being rationed.

The test that already happened

The 2026 Hormuz closure ran the experiment in miniature. Taiwan had 22 liquefied natural gas vessels due through the strait across March and April, and about a third of its gas comes from Qatar. Its ministry stated that supply would be unaffected because the shortfall could be covered by emergency procurement and expedited delivery, with three contingencies behind that: non-Middle Eastern sources, mutual assistance with Japan and South Korea, and buying existing cargo on the spot market. Talks were reported to divert Japanese-contracted shipments to Taiwan.

It held. But read what holding required: cargo bought at spot prices, a friendly supplier willing to give up its own delivery, and a disruption confined to one strait while the rest of the ocean kept working. In a regional conflict, Japan and Korea are not surplus holders with cargo to spare. They are competitors for the same diverted molecules, and the sellers are looking at the same risk premiums that closed the strait in the first place.

The mechanism that saved Taiwan in March is the mechanism that fails first when the disruption is general rather than local.

6. The return leg: containers, vehicles and plant

Port authority throughput figures and industry reporting; national import splits not yet compiled

Everything above this section is bulk. Bulk is what a country sends out, or what it burns. Containers are what comes back, and they are the half of the trade that decides whether a modern economy can function rather than merely generate power.

The scale, and where it concentrates

Global container throughput reached about 937 million twenty-foot equivalent units in 2024. The Asia-Pacific handles the overwhelming majority of it, and nine of the world’s ten busiest container ports are in the region.

Two things in that table matter more than the ranking. The first is that about 85 per cent of Singapore’s throughput is transshipment — boxes that arrive on one ship and leave on another, belonging to somebody else’s trade. A disruption at Singapore is therefore not a Singaporean disruption. It is a disruption to Manila, Jakarta, Colombo and every feeder port in the network, none of which has an alternative of similar depth.

The second is Hong Kong. It was the busiest container port in the world in 2004 and is now outside the top ten, not because anything happened to it, but because mainland ports built their own capacity and carriers quietly changed their networks. A hub’s volume belongs to its customers, not to the port. That is worth remembering by anyone who assumes traffic will simply reroute in a crisis: it reroutes when carriers choose to, on commercial terms, over years.

Vehicles

Cars arrive on their own ships. Pure car and truck carriers are a specialised fleet, and the trade runs almost entirely one way in this region: Japan, South Korea and now China build them, and everyone else buys them.

Australia is the extreme case. The last vehicle assembly plant closed in October 2017. Since then every new car, truck, bus, tractor and piece of mobile plant used in Australia has arrived by ship, at something over a million vehicles a year. There is no domestic capacity to fall back on, no partial substitution, and no stockpile: dealer inventory is measured in weeks and the replacement rate assumes uninterrupted delivery.

That is not a consumer problem. The mine haul fleet, the agricultural fleet, the truck fleet that moves food, and the ambulances all come from the same lanes as the fuel that runs them. An interruption long enough to matter takes both at once, and the second one does not recover when the ships resume, because a vehicle fleet is replaced over years rather than restocked in weeks.

Industrial plant

The heaviest and least substitutable category is capital equipment: transformers, turbines, switchgear, high-voltage cable, mining and processing plant, and the machine tools that make everything else. These move as breakbulk and project cargo rather than in containers, and they are the reason a supply interruption compounds instead of pausing.

The lead times are already extreme without a crisis. Large power transformers run to well over two years from order to delivery, high-voltage circuit breakers and switchgear to about the same, and gas turbines are sold out into the 2030s. Australia manufactures almost none of it. So an interruption does not simply delay the equipment; it lands on a queue that is already years deep, behind buyers who did not have their orders interrupted.

This is where the container trade meets the argument of this memo. A country can ration fuel and it can ration food. It cannot ration a transformer that has not been built, and it cannot decide to build one in under two years without an industry that no longer exists.

What the return leg means

Read against the bulk chart, the picture completes. The economies at the top of that chart export raw material and import the finished goods made from it — Australia ships iron ore and buys back steel products, vehicles and plant; Indonesia ships coal and buys back refined fuel and machinery. The economies at the bottom import the raw material and export the goods.

Neither half works without the other, and both halves cross the same water in opposite directions. A blockade aimed at one direction stops both.

7. China

Customs-sourced

China moves more bulk than any other economy in the region and sends almost none back: iron ore 572 arrivals a month, coal 565, grain 203, crude 184 and gas 92. It takes in the raw material for everything it makes.

Its power is secure and its inputs are not. Roughly 80 per cent of its crude still transits Malacca, and the overland pipelines from Kazakhstan, Russia and Myanmar carry about a tenth of oil imports. Beijing named that vulnerability in 2003 and two decades of reserves, pipelines and rail have not closed it. A blockade of China is a campaign measured in years, and the same water carries the ore and coal its steel industry runs on.

8. Australia

Iron ore and LNG from Australian sources; other cargoes carried forward

Australia is the mirror image: 923 cargoes out a month against 78 in. Iron ore 417 sailings, coal 364, gas 98, grain 36. The imports are almost entirely refined product.

Australia exports oil and imports fuel, and the two are not the same thing. It produces about 320,000 barrels a day of crude and condensate and exports roughly 96 per cent of it — light, sweet oil from the North West Shelf that Asian refineries pay a premium for, shipped north to Singapore, South Korea, China, Japan, Thailand and Malaysia. The two refineries that remain, with a combined capacity of about 235,000 barrels a day, need a heavier blended feedstock, so they import crude as well. The imports are almost all refined product, and the scale of that is not widely understood: at 50.8 million tonnes in 2024, Australia is the fifth largest importer of refined petroleum product in the world, behind only the European Union, the United States, Singapore and France. The exports are the national income and the imports are the national vulnerability. Two refineries remain from eight in 2005, roughly 90 per cent of liquid fuel is imported, and reserves have been reported at 22 days of diesel against a 90-day obligation. The grid runs on domestic coal and gas and survives an interruption. The trucks, harvesters, haul fleet and freight rail do not, and neither does the vehicle fleet: every new vehicle has arrived by ship since the last assembly plant closed in 2017.

9. Indonesia

Cargo carried forward; crude dependence from IEEFA

Indonesia ships about 581 cargoes out a month, 558 of them coal, against 70 in.

It is the world's largest thermal coal exporter and the largest supplier to China, and it sits astride the archipelagic straits that everything else passes through. Its own generation runs on its own coal. Its transport fuel does not: domestic refining does not meet demand, so it ships coal to the region and buys back the fuel its trucks run on. An economy that controls the passages and still imports its fuel through them is exposed twice.

10. Japan

LNG and coal from trade statistics; crude and grain carried forward

Japan takes about 321 cargoes a month and sends almost none out: coal 171, gas 95, crude 32, grain 23.

It produces about 13 per cent of the energy it uses, imports around 65.9 million tonnes of LNG and 171 million tonnes of coal a year, and refines its own crude, which is why its oil arrives in fewer and larger cargoes than Australia's. It holds about nineteen days of gas in above-ground tanks, with no underground storage and no pipeline to anywhere. The 1941 embargo and the submarine campaign that followed are in the Strategic Bombing Survey, and the geography has not changed.

11. Taiwan

LNG and coal from trade statistics; crude and grain carried forward

Taiwan takes about 109 cargoes a month: coal 54, gas 44, grain 6, crude 4.

It imports about 97 per cent of its energy into an island with eleven days of gas storage, against 140 to 146 days of oil that oil-fired plant of 4.7 per cent of capacity cannot burn. Its last reactor closed in 2025. Its exposure is not primarily military: a quarantine that slowed arrivals would bite before any landing, and the lanes it depends on carry Japanese and Korean cargo too, which is why an interruption there is not containable to one party.

12. South Korea

Generation mix and gas inventories from energy agencies; cargo not yet compiled

South Korea has no cargo column in this dataset yet. It belongs here on every other measure: it is among the world's largest importers of both liquefied natural gas and coal, taking about 115.58 million tonnes of coal a year.

Its energy position is Japan's with a nuclear fleet attached. The reported self-sufficiency figure of 22 per cent falls to 4.6 per cent once nuclear is excluded, and the uranium arrives by sea like everything else, though on a cycle of months rather than days. It holds about thirty days of gas, the largest buffer in the region and still a month, with no underground storage and no pipeline to a neighbour, which for a peninsula bordered to the north by the DPRK is geography rather than policy.

13. Singapore

Energy statistics from published sources; cargo not yet compiled

Singapore has no cargo column either, and its absence matters more than the others, because much of the region's traffic passes through it rather than ending there. Its container port handled 41.1 million twenty-foot equivalent units in 2024, about 85 per cent of it transshipment.

It imports about 98 per cent of its energy and generates almost all of its electricity from gas, with no domestic resource of any kind. It is also the region's refinery and bunkering hub: crude arrives, is refined, and leaves as the product that fuels other people's trucks and ships, including a meaningful share of Australia's. An interruption at Singapore is therefore not one country's problem. It removes refining capacity and marine fuel from the entire system at once.

14. The Philippines

Generation mix from the Department of Energy; cargo carried forward

The Philippines takes about 100 cargoes a month, spread across coal 37, refined product 35, gas 16 and grain 12.

It generated 126.9 terawatt hours in 2024, 62.2 per cent of it from coal, and its coal imports have tripled since 2010 to about 41 million tonnes. Crude import dependence is 97 per cent, the highest in South-East Asia. An archipelago of more than seven thousand islands moves its domestic freight by sea as well as its imports, so a disruption in the lanes compounds inside the country rather than stopping at the port, and the Malampaya field's decline is now pulling it into the LNG market as well.

15. New Zealand

Generation from Transpower; cargo carried forward

New Zealand takes about 17 bulk cargoes a month, the smallest figure here and the most misleading.

Its generation is about 87 per cent renewable, so the grid is among the cleanest and least exposed in the region. Its fuel supply is the opposite. The Marsden Point refinery closed in 2022, so the country now imports finished product exclusively, on a long haul from Asian refineries into a market too small to attract redundant supply. A low vessel count is not resilience: fewer ships carry a larger share of what arrives, and the loss of any one of them matters more.

16. Papua New Guinea

Indicative; cargo carried forward

Papua New Guinea ships about 11 LNG cargoes out a month and takes in almost nothing in bulk.

It is the region's clearest example of a resource economy without an industrial one: gas leaves, and refined product, machinery and food arrive in containers and small parcels this measure does not capture. Its position on the northern approaches to Australia, and the absence of any pipeline connection to it, is the subject of a separate memo in this series.

17. Sri Lanka

Indicative; cargo carried forward

Sri Lanka takes about 14 bulk cargoes a month, mostly refined product with a little coal.

It is on this list because of what happened in 2022. Shipments halted, fuel was rationed, inflation reached 54.6 per cent and the government fell inside months. No blockade was imposed and no shot was fired; the country simply ran out of foreign exchange to pay for cargoes. It is the working demonstration that an import-dependent island does not need to be attacked to stop, and the only case here where the failure has already run to its conclusion.

18. India

Indicative; crude dependence from IEEFA; cargo not yet compiled

India has no cargo column here yet. It is the world's second largest coal importer after China, at about 233 million tonnes a year, concentrated in the higher grades its domestic mines cannot supply.

Coal supplied close to 75 per cent of Indian electricity in 2023 and most of it is its own, so the grid is comparatively insulated. The oil is not: 85 to 90 per cent of crude and 45 to 50 per cent of gas are imported, and the crude arrives through Hormuz and across the Indian Ocean. India is the largest economy on this page and sits at the western end of every lane in it.

19. Vietnam

Indicative; crude dependence from IEEFA; cargo not yet compiled

Vietnam has no cargo column here yet, and its position has changed faster than any other economy on this page.

It was a coal exporter. It is now a substantial coal importer, with about half its electricity coal-fired and demand growing faster than domestic supply. Crude import dependence is 92 per cent, the highest of the mainland South-East Asian economies. A country that moved from selling into this trade to buying from it inside two decades is the clearest illustration that these positions are not fixed.

20. Thailand

Indicative; crude dependence from IEEFA; cargo not yet compiled

Thailand has no cargo column here yet. Its coal imports have risen about 365 per cent since 2000, and its domestic gas is declining while its gas-fired generation is not.

Crude import dependence is 58 per cent, and Thailand refines at home and exports product, so its exposure is to the crude arriving rather than to the diesel. The gas is the faster problem: as the Gulf of Thailand fields deplete, an economy built on domestic gas is being converted into one built on liquefied imports, and about a quarter of those imports came from the Middle East in 2024.

21. Malaysia

Indicative; crude dependence from IEEFA; cargo not yet compiled

Malaysia has no cargo column here yet, and it is the most contradictory position in the region.

It is one of the world's leading exporters of liquefied natural gas, and it burns imported coal to make most of its electricity, having shifted from gas to coal-fired power as it became more profitable to sell the gas abroad. Crude import dependence is 36 per cent and refined product exposure only about 8 per cent, because it refines at home. It sits on the Strait of Malacca, and its own gas fields are in the South China Sea.

22. What this means for a blockade

Read the chart once and it looks like fifteen economies with fifteen exposures. Read it twice and it is one system counted from both ends.

Every bar appears twice

Australia ships 417 iron ore cargoes a month; China receives 572. They are largely the same ships. Indonesia sends 558 coal cargoes out; the Philippines, China, Japan and Korea take them in. Malaysia exports about 25 million tonnes of liquefied gas; Japan, Korea, China and Taiwan burn it. And Australia’s crude leaves for Singapore, Korea, Japan and Malaysia, is refined there, and returns as part of the 50.8 million tonnes of finished product in Australia’s own import column — 6 million tonnes of it from Malaysia alone.

That is not a metaphor about interdependence. It is the same cargo, on the same voyage, entered twice in this dataset because it is counted once when it leaves and once when it arrives.

Two economies cannot substitute inward at all

Australia produces about 320,000 barrels a day of crude and exports 96 per cent of it, because its light sweet grades earn a premium abroad and its two remaining refineries need a heavier blend. Vietnam does the same thing for the same reason: it exports its own crude and imports different grades, because Dung Quat and Nghi Son were built for oil its fields no longer produce.

Both countries could stop exporting tomorrow and would be no better fed with fuel, because their own oil is the wrong oil for their own refineries. The trade is not a preference that could be reversed under pressure. It is a physical requirement.

The arithmetic of interdiction

Set the two halves against each other. A campaign to close a lane takes months to assemble: a naval deployment takes weeks to position, a convoy system takes weeks more to organise, and the commercial confidence that actually restarts traffic took months to return to the Red Sea after the last attack.

The countries on the receiving end hold eleven days of gas in Taiwan, nineteen in Japan, twenty-two days of diesel in Australia and thirty in Korea.

The aggressor is on the same clock. A power interdicting Australian ore stops its own steel. A power interdicting tankers bound for Asian refineries stops the diesel that its own trucks run on, because those are the same refineries. There is no configuration of this chart in which one participant’s traffic can be halted and the others continue, because the traffic is not fifteen separate flows. It is one circulation with fifteen names on it.

What follows from that

The conclusion is arithmetic rather than sentiment. A blockade in this region is not a strategy that might fail. It is a strategy that closes on the party executing it at roughly the same speed as on the target, and faster than the fleet conducting it could be assembled.

Three things follow, and they are the reason this memo exists.

The exposure is mutual. The economy most often named as the threat is the most sea-dependent of them all, and its ore, coal, gas and soybeans cross the same narrows as everyone else’s.

The bystanders are not spared. A conflict between two parties stops the trade of fifteen, because the underwriters withdraw from the area rather than from the flag.

And the smallest number on the chart is the most dangerous. New Zealand’s thirteen cargoes a month and Sri Lanka’s six are not evidence of resilience but of thin supply into markets too small to attract redundancy. Sri Lanka in 2022 is the demonstration: no blockade, no attack, simply an inability to pay for cargoes, and a government gone inside months.

Which leaves the question this memo was built to answer. Not who would win a war over these lanes, but how long anyone would last while the question was being settled. On the evidence above, not long, and least of all the country holding twenty-two days of diesel at the far end of every one of them.

23. What follows from the data

This memo counts ships. It does not argue a policy, and everything below is argued elsewhere — but the numbers point somewhere, and it would be dishonest to pretend they do not.

How a lane actually closes

Nothing above explains the mechanism. That is set out in The Proof of the Hormuz Pudding: premiums, cover, and the forty-eight hours in February 2026 in which the strait emptied before a mine was laid. The insurance market disputes part of that account, and the memo carries the dispute.

What a siege does to a country that cannot feed itself

Three thousand years of siege history against two defence policies is The Island Castle. It is the long form of the argument this memo supplies the arithmetic for: sieges are decided by what is inside the walls, and Australia’s walls hold twenty-two days of diesel.

What the refineries cost

The True Cost of Cheap Imported Fuel and Australia’s Transport Fuel Problem take the fifth-largest-importer figure in this memo and set out what it cost to arrive there, and what it would take to leave.

That resilience is built, not bought

One country in this dataset spent two decades preparing for exactly the scenario the others assume will not happen. How China Held the World Up is the record of what that looks like when a chokepoint actually closes.

What the submarines are measured against

Building the Sub to Nowhere sets the submarine programme against the shipping it is meant to protect, and The Holes in AUKUS and the Australian Defence Plan is the register of every documented defect in that plan, numbered and sourced.

And what the alternative is

The traffic on this chart is the strongest argument that exists for not fighting over it. That case is made in The AsiaPac Predicament, proposed in The AsiaPac Solution, and set out as a positive vision in The Prize: A Unified AsiaPac. The posture that follows from it is on the AUASIA page.

The reason to read them in that order is that this memo makes the conclusion unavoidable rather than attractive. Every economy here runs on the same water, in both directions, and the cargo that would be interdicted is the cargo the interdicting power also needs. A war over these lanes is not a contest anyone wins slowly. It is a system that stops, including for whoever stopped it.

24. Appendix: method, scope and limits

One calibration against a real port

A model derived from tonnage is worth checking against somebody who counts ships. The Port of Port Hedland does. In 2021–22 it recorded 3,281 vessel arrivals against 561 million tonnes of cargo, which implies an average parcel of about 171,000 tonnes. The figure used in this memo for iron ore is 180,000 tonnes, a variance of about five per cent.

That is one trade at one port, and it is not a validation of every cell in the table. It does say the method is in the right range rather than the wrong one, and it is the sort of check that should be repeated for crude, coal and gas as port-call data becomes available.

Why these economies

Fifteen economies are counted here, and they are not a complete list of the region. Hong Kong, Bangladesh, Pakistan and Brunei sail the same water and are not yet in this dataset.

One caution about that group. The figure available for them is crude oil import dependence — how much of the oil they refine comes from abroad — which is not the same measure as the share of finished transport fuel imported that is used for the other economies. Malaysia at 36 per cent and Thailand at 58 per cent both refine at home and export product; their exposure is to the crude arriving, not to the diesel. The two measures are shown together because they answer the same question about a lane, but they should not be read as identical. On the vulnerability chart those four sit in a third group, between the economies that import the fuel for both their power and their transport and those that generate from their own resources.

Two of the eleven are included as demonstrations rather than as large flows. Papua New Guinea shows the shape of a resource economy without an industrial one. Sri Lanka shows what happens when an import-dependent island cannot pay, which is the only case in this set where the failure has already run to its conclusion.

What this memo does not model

It is worth being explicit, because a count of hulls invites more weight than it can carry. This memo does not model war risk premiums or the availability of cover, naval escort capacity or the time required to assemble it, the percentage offset available from pipelines and overland routes, the contents of containers as distinct from their number, food stocks or agricultural inventories, or the behaviour of governments under pressure.

It counts ships and days. Everything else in the argument — and everything above about how a lane actually closes — is drawn from the memos this one sits beside, and is cited rather than modelled here.

25. Sources

1. General Administration of Customs of the People's Republic of China, 2024 trade data: crude oil imports of 553.42 million tonnes (11.04 million barrels a day), coal imports of 542.7 million tonnes, iron ore imports of 1,236 million tonnes.
2. Chinese liquefied natural gas and grain import volumes are widely reported at approximately 77 and 158 million tonnes respectively for 2024, and are being pinned to customs releases.
3. UN COMTRADE and World Bank WITS: Japanese liquefied natural gas imports of 65.89 million tonnes, 2024.
4. International Gas Union, World LNG Report 2025: Taiwanese liquefied natural gas imports of 21.8 million tonnes, 2024.
5. United States Energy Information Administration derived series: Japanese coal imports of 171.06 million tonnes and Taiwanese coal imports of 56.98 million tonnes, 2024.
6. Geoscience Australia and the Department of Industry, Science and Resources: Australian liquefied natural gas exports of approximately 81 million tonnes and metallurgical coal exports of approximately 163 million tonnes; iron ore exports of approximately 900 million tonnes.
7. Vessel class definitions: very large crude carriers of 200,000 to 320,000 deadweight tonnes carrying about two million barrels; Capesize of 100,000 to 200,000 deadweight tonnes carrying about 70 per cent of seaborne iron ore; Panamax of 65,000 to 100,000 deadweight tonnes on the major coal and grain routes.
8. Cargo splits for Indonesia, Japan, Taiwan, the Philippines, New Zealand, Papua New Guinea and Sri Lanka are tonnages implied by the earlier version of this chart, re-divided by the parcel sizes above. They are consistent with the totals previously published by this movement and are being replaced with customs and agency figures.
9. Energy self-sufficiency: Japan at about 13 per cent and Korea at about 19 to 22 per cent (International Energy Agency, World Energy Investment 2025; Korea Energy Economics Institute, 2024, giving 22.1 per cent including nuclear and 4.6 per cent excluding it); Japan’s own Agency for Natural Resources and Energy reports 12.6 per cent for FY2022. Singapore at about 98 per cent import-reliant. Taiwan at about 97 to 98 per cent.
10. Taiwan electricity generation 2024: 288 terawatt hours, 83.2 per cent fossil fuel (42.4 per cent natural gas, 39.3 per cent coal), 4.2 per cent nuclear, 11.6 per cent renewables. Oil-fired plant is about 4.7 per cent of installed capacity (Taipower).
11. Gas storage: Taiwan’s statutory security stockpile is 11 days, rising to 14 by 2027, with about 140 to 146 days of crude oil held (Ministry of Economic Affairs; Chung-Hua Institution for Economic Research; Center for Strategic and International Studies, June 2026). Japan holds an average of about 19 days and South Korea about 30 days of liquefied natural gas in above-ground tanks, with no underground storage or pipeline interconnection (United States Energy Information Administration).
12. Hormuz 2026: 22 Taiwanese liquefied natural gas vessels were due through the strait in March and April, with about a third of Taiwanese liquefied natural gas sourced from Qatar; the shortfall was covered by emergency procurement and redirected cargoes (Ministry of Economic Affairs; Atlantic Council; Taipei Times).
13. Chokepoint volumes: United States Energy Information Administration, World Oil Transit Chokepoints, for the shares of seaborne oil and liquefied natural gas passing the Strait of Malacca and the Strait of Hormuz; Malacca is about 2.8 kilometres wide at its narrowest navigable point.
14. Routing: a diversion from Malacca to the Lombok Strait adds approximately three days to a voyage between the Persian Gulf and North Asia; Lombok is the established route for the deepest-draught ore carriers, which cannot transit Malacca fully laden.
15. Republic of Korea: coal imports of approximately 115.58 million tonnes, 2024 (United States Energy Information Administration derived series); generation mix from the Korea Power Exchange; liquefied natural gas inventories averaging about 30 days (United States Energy Information Administration).
16. Singapore: energy import dependence of approximately 98 per cent, with electricity generated almost entirely from natural gas.
17. Container throughput 2024: global 937 million twenty-foot equivalent units; Shanghai 51.5 million, Singapore 41.1 million of which approximately 85 per cent is transshipment, Busan 24.4 million, Tianjin 23.3 million, Port Klang 14.6 million, Hong Kong 13.7 million (port authorities, Lloyd’s List and Container News).
18. Australian vehicle assembly ceased in October 2017 with the closure of the last plant; all new vehicles are now imported, at something over a million units a year.
19. Capital equipment lead times: large power transformers averaging above two years, high-voltage circuit breakers comparable, and gas turbine order books extending into the 2030s, as set out in The Energy Generator Queue.
20. Calibration: the Port of Port Hedland recorded 3,281 vessel arrivals against 561 million tonnes of cargo in 2021–22, implying an average parcel of about 171,000 tonnes against the 180,000 tonnes assumed here (Pilbara Ports Authority).
21. Pilbara Ports monthly throughput in 2024 ran between about 52.7 and 68.8 million tonnes, of which Port Hedland iron ore exports were between 38.8 and 51.9 million tonnes; over 7,000 bulk carriers visited the Pilbara ports in 2023–24, about half of them for iron ore.
22. Crude oil import dependence, 2025 data: Indonesia 25 per cent, Malaysia 36 per cent, Thailand 58 per cent, Vietnam 92 per cent, the Philippines 97 per cent (Institute for Energy Economics and Financial Analysis).
23. India: coal supplied close to 75 per cent of electricity in 2023 and is largely domestic, with imports concentrated in higher grades at about 233 million tonnes; 85 to 90 per cent of crude oil and 45 to 50 per cent of gas are imported.
24. Malaysia: natural gas is about 43 per cent of primary energy supply and about a third of electricity generation, with coal supplying the larger share of power; Thailand: coal imports have risen about 365 per cent since 2000 and domestic gas is declining against rising liquefied natural gas imports.
25. Coal imports 2024, single series: China 542.78 million tonnes, India 232.81, Japan 171.06, the Republic of Korea 115.58, Taiwan 56.98, Vietnam 49.83, Malaysia 39.34, the Philippines 39.29, Thailand 31.76, New Zealand 1.01, Sri Lanka 0.83.
26. India: crude oil imports of 232.5 million tonnes in the 2023–24 financial year, with import dependence at 87.7 per cent (Petroleum Planning and Analysis Cell).
27. Thailand: crude oil imports of about 972,000 barrels a day in 2024, an all-time high (OPEC via CEIC), and liquefied natural gas imports of more than 11.7 million tonnes in 2024.
28. Malaysia: liquefied natural gas exports of about 25 million tonnes in 2024 across roughly 398 cargoes from the Bintulu complex, whose nine trains have a capacity near 29 million tonnes a year; liquefied natural gas imports of 3.3 million tonnes in 2024, up from 2.1 million in 2021, with projections that Malaysia could become a net importer within ten to twenty years.
29. Vietnam exports its own crude and imports different grades for the Nghi Son and Dung Quat refineries, which are configured for crudes its domestic fields no longer supply; a tonnage for those imports is not yet compiled.
30. Malaysia: crude petroleum exports of 9.31 million tonnes in 2023 (Statistics Malaysia) and refined petroleum product exports of 37.8 million tonnes in 2024, principally to Singapore, Indonesia, Australia, Vietnam and Bangladesh (UN COMTRADE, HS 2710).
31. Crude oil imports, UN COMTRADE HS 270900, 2023, in million tonnes: China 553.99, India 235.26, the Republic of Korea 134.0, Japan 125.14, Taiwan 39.40, Malaysia 21.07, Indonesia 17.84, Vietnam 10.41, Australia 9.03, the Philippines 7.18, Papua New Guinea 0.11. The Thai entry in that series is anomalous and the figure used here is from OPEC.
32. Liquefied natural gas imports, UN COMTRADE HS 271111, 2024, in million tonnes: China 76.57, Japan 65.89, the Republic of Korea 46.32, India 27.79, Taiwan 19.94, Thailand 11.42, Singapore 6.78, Malaysia 3.25, the Philippines 1.19.
33. Refined petroleum product imports, UN COMTRADE HS 271000, 2024, in million tonnes: Singapore 84.92, Australia 50.79, China 48.23, Malaysia 36.88, the Republic of Korea 36.74, Indonesia 28.73, Japan 24.34, the Philippines 14.57, India 13.93, Taiwan 13.71, New Zealand 8.75, Thailand 8.40, Sri Lanka 3.68. Australia ranks fifth in the world on this measure, behind only the European Union, the United States, Singapore and France.
34. Iron ore imports, UN COMTRADE HS 260111, 2023, in million tonnes: Japan 93.97, Taiwan 19.08, Vietnam 14.39, India 4.70, New Zealand 0.14; Chinese imports of 1,236 million tonnes are from customs, 2024. Where a reporter gives value without quantity — the Republic of Korea, Malaysia, Indonesia and the Philippines — tonnage is derived at the Japanese unit value of about $107.8 a tonne. That method reproduces the Chinese customs figure to within 1.4 per cent, which is the check on it.
35. Soybean imports, UN COMTRADE HS 120100, 2022, in million tonnes: China 91.08, Japan 3.50, Thailand 3.02, Indonesia 2.32, Vietnam 1.84, Malaysia 0.72, India 0.49, the Philippines 0.16. Taiwan and the Republic of Korea report value without tonnage and are derived at the Chinese unit value of about $672 a tonne. Wheat and maize are not yet counted.
36. Australia produces about 320,000 barrels a day of crude oil and condensate and exports roughly 96 per cent of it, principally light sweet grades from the North West Shelf, to Singapore, the Republic of Korea, China, Japan, Thailand and Malaysia; the remaining two refineries have a combined capacity of about 235,000 barrels a day and require a heavier blended feedstock, which is why crude is imported as well (Geoscience Australia; Australian Institute of Petroleum; Royal Australian Navy, Soundings No. 7).
37. Sri Lanka 2022: fuel rationing, inflation of 54.6 per cent, and the fall of the government following the suspension of shipments, as recorded in contemporaneous reporting and examined in The Island Castle.