What China’s submarine missile test reveals about its nuclear strategy

China’s 6 July missile test was easy to read as another dramatic episode in a crowded summer of military activity. A Chinese strategic nuclear submarine fired a missile carrying a dummy warhead into a designated area of the Pacific. Beijing described it as routine annual training and said relevant countries had been notified in advance. 

Proving second-strike capability

The launch came less than two years after China tested a land-based intercontinental ballistic missile into the Pacific in September 2024. Taken together, the two tests tell a simple story. The 2024 launch showed that China could strike at intercontinental range. The submarine launch was meant to show that China could still retaliate even if part of its land-based nuclear force had already been destroyed. 

That is the central purpose of a nuclear-armed submarine. Hidden at sea, it is harder to find and eliminate than a missile silo or an air base. Its value lies less in adding another weapon than in making a disarming first strike far less plausible.

The July test matters because it tested an entire system. The submarine had to receive orders, navigate underwater, launch safely, guide the missile towards its target area and remain able to survive after firing. China was demonstrating that the submarine, missile, crew, communications and command system could operate as a single retaliatory chain.

This fits the direction Beijing has publicly set for its nuclear forces. China’s 2025 arms control white paper and its 2026 report under the Nuclear Non-Proliferation Treaty say the country is improving early warning, command and control, missile penetration, rapid response and survivability. Beijing also continues to describe its posture as defensive, maintains a no-first-use policy and says it keeps its nuclear forces at the minimum level required for national security. 

The apparent contradiction is easier to understand once “minimum” is treated as a level of security rather than a fixed number of warheads. A small arsenal may be enough only if some of it is certain to survive an attack. As US missile defence, precision conventional weapons, cyber capabilities, satellites and anti-submarine systems improve, China’s estimate of what it needs for a credible minimum can also rise.

Sounding a warning to the US

Independent assessments nevertheless show why other countries are concerned. The Stockholm International Peace Research Institute estimates that China had about 620 nuclear warheads by early 2026 and describes its arsenal as the world’s fastest expanding. The exact number is uncertain because China does not publish a detailed warhead inventory, but the broader trend is clear. China is adding delivery systems and improving the infrastructure needed to keep them protected and ready. 

The test’s principal audience was the US and, more broadly, other nuclear powers. A long-range submarine-launched missile has little direct military relevance to Taiwan, Japan, the Philippines or Australia. Its purpose is to shape decisions at the highest level of a major-power crisis.

Beijing wants Washington to understand that a conventional conflict in East Asia cannot be turned into an attempt to destroy China’s nuclear force without creating a risk of retaliation. A survivable submarine fleet makes it harder to believe that precision strikes, cyber operations, missile defence and anti-submarine warfare could neutralise China’s response.

In that sense, the test may support strategic stability. Mutual vulnerability is uncomfortable, but it can reduce the temptation to seek a decisive first-strike advantage. A more secure Chinese second-strike force could make both sides more cautious in an extreme crisis.

China’s ‘selective transparency’

The launch also clarified Beijing’s approach to transparency. China disclosed the broad purpose of the test and said relevant countries had been notified, but it did not identify the missile, submarine, launch point, range or landing zone in detail. This is selective transparency, enough to reduce the risk that a test is mistaken for an attack while withholding information China considers sensitive.

That approach matches Beijing’s broader arms control position. China stresses “no first use”, security guarantees for non-nuclear states, advance notification and multilateral risk reduction. It also argues that the US and Russia, whose arsenals remain much larger, should make deeper reductions before China joins negotiations on numerical limits. Beijing wants a secure retaliatory capability before accepting restrictions that could lock in strategic inferiority. 

Complementing regional institutions

The test also belongs to a wider regional setting. Asia now operates through three overlapping forms of multilateral groupings. ASEAN-centred regional functionalism preserves trade, dialogue and practical cooperation. The US-led security alliance is being networked through bases, intelligence, logistics, missiles and increasingly complex exercises. China-Russia-led counter-alignment spectrum is expanding strategic coordination without creating a formal alliance. Many regional states participate across more than one of these tracks rather than joining a sealed bloc. 

The missile test was a sovereign Chinese action, yet its timing alongside China-Russia military activity and the recent US-led large-scale exercises in the region, reinforced the impression that Asia’s two security tracks are becoming harder and more capable, while the region’s cooperative institutions remain poorly equipped to manage nuclear risk.

A stronger Chinese second-strike force does not automatically make Asia less stable, and efforts to deny China any credible retaliatory capability would be unrealistic and dangerous. But capability alone cannot produce lasting stability.

Beijing and Washington need regular nuclear discussions, clearer crisis communications, stronger missile test notification arrangements and a better shared understanding of which attacks on warning and command systems could trigger uncontrollable escalation. Regional institutions cannot negotiate the US-China nuclear balance, but they can support norms of notification, restraint and crisis prevention.

China’s submarine launch shows that Beijing intends to remove strategic vulnerability before accepting strategic constraint. That may create a more balanced nuclear relationship with the US. Whether it also creates a safer Asia will depend on whether diplomacy and risk reduction can develop as quickly as the weapons they are meant to govern.

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