
Taiwan’s long-anticipated flagship submarine, the Hai Kun — meaning Narwhal — has missed a crucial sea trial deadline, casting a shadow over one of Asia’s most ambitious defense projects and exposing the limits of Taiwan’s industrial and strategic reach in the face of mounting Chinese pressure.
This month, the South China Morning Post (SCMP) reported that Taiwan’s Indigenous Defense Submarine (IDS) program suffered a serious setback in September, raising doubts over whether the $1.5 billion vessel could be delivered to the Navy by its long-stated November target.
Defense Minister Wellington Koo Li-hsiung admitted that meeting the deadline would be “quite challenging,” acknowledging repeated technical problems that have plagued the Hai Kun since surface tests began in June.
The Hai Kun — the first of eight planned domestically built submarines — spent weeks in dry dock following its third sea trial in July, prompting speculation among defense analysts that deeper structural or engineering faults were uncovered. According to retired Navy captain Huang Cheng-hui, the issues likely stem from suspected leaks in the main engine’s cooling system, problems that may require major disassembly to correct.
“If the leaks are confirmed, it’s not just a matter of fixing pipes — it could point to a misalignment in how the propulsion and cooling systems were integrated,” Huang told local media. “That would require a fundamental redesign and push the project back by months.”
The Hai Kun project is emblematic of Taiwan’s determination — and its constraints. Cut off from most international arms markets by Beijing’s diplomatic isolation campaign, Taiwan has been forced to piece together its submarine from components sourced across multiple countries, often through complex or discreet arrangements.
The result, according to one senior defense official, is “a United Nations of systems” — a vessel integrating sonar arrays, periscopes, and combat systems supplied by the U.S., the U.K., Japan, and several European partners, all under strict secrecy.
U.S. defense giant Lockheed Martin, tasked with integrating the Hai Kun’s combat system, has reportedly faced severe synchronization challenges between disparate subsystems. “Every supplier uses different standards, interfaces, and software architectures,” one program insider told SCMP. “It’s like trying to make a symphony with instruments that were never meant to play together.”
The engineering challenge is formidable. Submarines are among the most complex machines ever built — a delicate equilibrium of hydrodynamics, stealth acoustics, and high-pressure systems. For Taiwan’s limited shipbuilding industry, achieving NATO-grade integration under tight deadlines and diplomatic constraints is a herculean task.
Taiwan’s Legislative Yuan (parliament) has frozen NT$1.8 billion (US$56 million) in funding for the remaining seven submarines until the Hai Kun passes its sea trials. That decision underscores growing unease in Taipei about the project’s technical viability — and its cost-effectiveness.
“The Hai Kun is the make-or-break test,” said Su Tzu-yun, director of the Institute for National Defense and Security Research (INDSR). “If it fails, it’s not just a technical setback; it’s a blow to Taiwan’s credibility in defense self-sufficiency.”
The IDS program has long been framed as a centerpiece of Taiwan’s asymmetric defense strategy — a doctrine aimed at offsetting China’s overwhelming numerical and technological superiority by fielding smaller, stealthier, and more survivable systems.
But as the Hai Kun falters, that narrative is being tested.
Taiwan’s military modernization has long been torn between conventional and asymmetric priorities. On one side are proponents of high-end conventional systems — fighter jets, frigates, and now submarines — which they argue are necessary to maintain deterrence and prestige. On the other are advocates of a “porcupine strategy,” emphasizing mobile, inexpensive, and easily concealed systems like drones, coastal missiles, and mines.
The Hai Kun sits awkwardly between these two camps. Submarines are quintessential asymmetric weapons: silent, elusive, and capable of striking from unexpected directions. Yet their cost, complexity, and vulnerability during maintenance make them a risky investment for an island with limited industrial depth and under constant threat of blockade.
Critics such as former defense official Luo Chih-cheng argue that the submarine program represents a “prestige trap” — a politically appealing but strategically inefficient use of scarce resources.
“Eight submarines, even if fully operational, can’t stop a blockade or invasion,” Luo said. “They may have symbolic value, but they don’t fundamentally change the balance of power.”
Proponents disagree. They contend that even a handful of stealthy submarines could disrupt China’s invasion planning, ambush vulnerable transport ships, and complicate the People’s Liberation Army Navy’s (PLAN) control of the Taiwan Strait.
“Submarines are about uncertainty,” said Rear Admiral Lee Hsi-ming (ret.), one of the architects of Taiwan’s “Overall Defense Concept.” “China can track every surface ship and aircraft Taiwan has — but not a submarine. That psychological deterrence alone is worth the cost.”
The debate over the Hai Kun mirrors a deeper strategic anxiety: Is Taiwan preparing for the right kind of war?
Over the past decade, China’s military posture has evolved from overt invasion threats to persistent “gray zone” operations — daily intrusions by Chinese aircraft, drones, and coast guard vessels designed to exhaust Taiwan’s resources and test its response thresholds.
Against such operations, stealthy submarines are largely irrelevant. “You can’t deter a visible provocation with an invisible platform,” one analyst at Academia Sinica noted. “Gray zone tactics thrive on visibility — on being seen but not crossing the line of open conflict. A submerged submarine has no signaling value.”
To respond to these intrusions, Taiwan has relied on fighter jets and frigates to show presence. Yet these high-profile assets would be the first to fall in a full-scale invasion, given China’s superior missile and satellite reconnaissance capabilities.
It’s a strategic paradox: the assets that reassure the public in peacetime are often the least survivable in wartime.
Some analysts frame this paradox as a lingering “US syndrome” — a mindset rooted in the Cold War era when Taiwan’s Kuomintang (KMT) leadership, backed by U.S. power, still dreamed of retaking the mainland.
That mentality fostered an attachment to high-end, high-visibility platforms — symbols of a modern, powerful state — rather than the low-cost, distributed systems that might better serve a smaller power facing a much larger adversary.
“Taiwan’s defense culture grew up in the shadow of American prestige weapons,” said Alexander Huang, a professor of strategic studies at Tamkang University. “The F-16s, the frigates, the tanks — they all represent an older model of deterrence. The submarine program may be the last echo of that era.”
In recent years, Taiwan’s military planners have shifted toward what they call the “porcupine strategy” — emphasizing survivability, dispersal, and attrition. The idea is to make any Chinese invasion painfully costly and protracted, denying Beijing a quick victory.
This includes investments in mobile missile launchers, naval mines, drones, and decoys, all designed to withstand the opening salvos of a Chinese attack.
A related concept, the “pit viper strategy,” envisions limited offensive strikes against Chinese staging areas, energy facilities, and military bases — enough to disrupt operations and buy time for U.S. and allied intervention.
Submarines like the Hai Kun could fit into this plan — especially if equipped with land-attack cruise missiles, giving Taiwan a second-strike capability. But without a fully integrated missile system and proven reliability, that role remains aspirational.
Beijing has multiple options for coercing Taiwan, ranging from full-scale invasion to “gray zone” blockade tactics that strangle the island without firing a shot.
A blockade could mirror China’s “cabbage strategy” in the South China Sea, where concentric layers of Coast Guard, militia, and naval vessels encircle contested features, supported by long-range missile coverage from the mainland.
In such a scenario, Taiwan’s submarines could theoretically disrupt maritime choke points or harass Chinese logistics lines — but they would face overwhelming anti-submarine warfare (ASW) measures. The PLAN has rapidly expanded its ASW aircraft, sonar networks, and underwater drones, eroding the traditional advantage of stealth.
Submarines might survive longer than surface ships in a blockade, but without resupply or external support, their endurance would be finite.
“A blockade is death by suffocation,” said a Taiwanese defense official. “Even if our submarines slip through, they can’t feed the island.”
A more direct — but riskier — option for Beijing would be a full-scale invasion. In this scenario, China could launch a rapid “decapitation strike” using ballistic missiles, cruise missiles, and special operations forces to neutralize Taiwan’s leadership and critical military assets before an effective defense could be mounted.
If successful, invasion forces could cross the Taiwan Strait within hours, leveraging air and missile superiority to establish beachheads and paralyze Taiwan’s command structure.
If such an operation failed, however, Taiwan could retaliate with long-range strikes — the “pit viper” counterplay — targeting Chinese bases, refineries, or industrial centers to sap Beijing’s war-making capacity. Submarines like the Hai Kun could, in theory, deliver such retaliatory blows from stealth.
But that capability cuts both ways. Any Taiwanese attack on mainland targets could galvanize Chinese nationalism, giving the Communist Party a rallying cry for escalation.
“Once Taiwanese missiles hit Chinese soil, the war becomes existential for Beijing,” said Bonnie Glaser, managing director of the Indo-Pacific Program at the German Marshall Fund. “It would unify the Chinese public behind the regime.”
If both deterrence and resistance collapse, Taiwan may be forced into what strategists call the “poison shrimp” strategy — making itself ungovernable and costly to occupy.
That would involve transitioning to guerrilla warfare, sabotage, and civil disobedience, supported by pre-positioned arms caches and covert communication networks. It’s a strategy of endurance — not victory — designed to bleed an occupier politically and psychologically.
Yet Taiwan’s geography limits this option. Unlike Vietnam or Afghanistan, it lacks overland supply routes or safe havens, making sustained insurgency difficult. Without outside intervention, China could eventually wear down resistance through attrition and repression.
“Taiwan’s geography is both its shield and its cage,” said one Western diplomat in Taipei. “It protects against quick invasion, but it also traps the defenders if the island is cut off.”
Ultimately, Taiwan’s survival depends less on any single weapons system and more on time, resilience, and alliance politics.
The United States remains Taiwan’s primary security guarantor, though its official stance of “strategic ambiguity” — declining to say whether it would intervene militarily — leaves the question deliberately open.
Washington has approved billions in arms sales to Taiwan, including Harpoon missiles, HIMARS rocket systems, and F-16V jets. Yet the Hai Kun project represents something different: a bid for self-reliance in a domain few nations dare to enter.
“Submarine building is the Everest of defense industries,” said Ian Easton, senior director at the Project 2049 Institute. “If Taiwan can do it, it shows the world that it’s not just a consumer of security — it’s a producer.”
But every delay, every cost overrun, every missed deadline chips away at that symbolism.
The Hai Kun’s troubles have revived uncomfortable questions about Taiwan’s defense priorities. For a democracy of 23 million facing a superpower of 1.4 billion, every defense dollar matters.
Supporters argue that the IDS program sends a message of resolve and deterrence — a technological “vote of confidence” in Taiwan’s survival. Detractors counter that it absorbs funds and expertise that could be used to mass-produce drones, missiles, or radar decoys — assets that might actually change the outcome of a war.
In 2025, with tensions rising and Chinese military drills now a near-daily occurrence, Taiwan’s room for strategic error is narrowing. The Hai Kun may yet sail — but its voyage now symbolizes more than a technical milestone. It represents the question haunting every defense planner in Taipei:
Is Taiwan building the weapons it needs for the war it will fight — or the war it remembers?