Japan’s economic security strategy is entering a harder phase. For much of the past decade, Tokyo’s supply chain policy has been framed around diversification away from excessive dependence on China. That remains necessary. But the Iran war has exposed a second vulnerability: Japan is not only dependent on specific suppliers. It is dependent on fragile routes, concentrated energy flows and an industrial geography that can be disrupted far from East Asia.
The near-closure of the Strait of Hormuz has made this painfully clear. Asia takes around 85% of Gulf crude shipments, and regional oil imports fell 30% in April after two months of severe disruption through the strait. Japan, which buys about 95% of its oil from the Middle East, has already increased purchases of U.S. crude and begun releasing 36 million barrels from stockpiles. This is not a temporary logistics inconvenience. It is a warning that Japan’s manufacturing base cannot be secured through domestic policy alone.
Tokyo appears to understand this. Prime Minister Sanae Takaichi’s recent visit to Vietnam placed energy, critical minerals, semiconductors, artificial intelligence and space cooperation at the center of Japan-Vietnam ties. Both sides identified economic security as a new priority, while Japan pledged support for crude oil supplies to Vietnam’s Nghi Son refinery under its $10 billion Power Asia Initiative. Takaichi also urged Southeast Asian nations to strengthen regional supply chains.
That message should now be widened. Japan does not merely need ASEAN as a market or an alternative production site. It needs ASEAN’s industrial geography.
For years, ASEAN’s value to Japan was described in familiar language: lower-cost manufacturing, demographic growth, political balance and proximity to China without being China. This was the grammar of “China plus one.” But the region’s strategic importance in 2026 is broader. ASEAN sits across the maritime and industrial middle of Asia. It links the Indian and Pacific Oceans, contains major electronics and automotive clusters, hosts critical ports and refineries, and provides Japan with a diversified production and logistics base across Vietnam, Thailand, Malaysia, Indonesia, Singapore and the Philippines.
The old question was where Japanese companies could move production if China became politically or commercially difficult. The new question is where Japan can build redundancy when energy routes, mineral supply chains, shipping insurance, fertilizer flows and currency stability are all under pressure at once.
This is why Vietnam matters, but also why Vietnam alone is not enough. Vietnam is increasingly central to electronics and consumer manufacturing. Reuters noted that Japanese investment in Vietnam fell sharply in the first quarter, even as bilateral trade rose 12.3% year on year to $13.7 billion and pledged investment for 2025 increased. The contradiction is revealing: companies see Vietnam’s importance, but the investment cycle is becoming more cautious because the surrounding risk environment is changing.
Japan’s task is therefore not simply to invest more in one country. It is to help build an ASEAN-wide industrial system with more depth.
Malaysia can support semiconductor assembly, testing, packaging, precision engineering and energy-linked manufacturing. Thailand remains a major automotive and electronics production base. Indonesia brings nickel, energy resources and a large domestic market. Singapore provides finance, logistics, arbitration and command-center functions. Vietnam offers scale in manufacturing and a growing role in electronics. The Philippines has strengths in services, electronics and human capital. None of these countries replaces China individually. Together, they offer something more useful: distributed resilience.
Japan’s partnership with Australia shows another piece of the same puzzle. Tokyo and Canberra have just agreed to strengthen cooperation on energy, food and critical mineral supply chains. Australia is also preparing up to A$1.3 billion in support for critical mineral projects involving Japan, including gallium, nickel, graphite, rare earths and fluorite
But Australia can provide resources; it cannot provide the full manufacturing geography Japan needs in Asia. ASEAN can. The strategic opportunity is to connect Australian and other resource flows with ASEAN processing, Japanese technology, and regional manufacturing demand. This would move Japan’s economic security policy beyond stockpiling and emergency procurement into a more durable industrial architecture.
The current energy shock also shows why supply chain resilience cannot be separated from macroeconomic stability. ASEAN+3 finance leaders recently reaffirmed their commitment to open trade, resilient supply chains and a WTO-centered multilateral system amid financial volatility. That statement matters because the Iran war is already affecting currencies, oil prices and inflation across Asia. In such conditions, industrial resilience is not only about whether a factory can operate. It is about whether the financial and trade environment around that factory remains predictable.
Japan should draw three lessons.
First, it should treat ASEAN as a network, not a set of bilateral relationships. Tokyo’s cooperation with Vietnam is important, but Japan should avoid creating disconnected national projects. Semiconductors, refined fuels, batteries, rare earths and industrial components require cross-border ecosystems. Japanese policy should map where each ASEAN economy fits into specific value chains, then finance the missing links.
Second, Japan should integrate energy security into manufacturing policy. The Hormuz crisis has shown that petroleum, LNG, refined fuels and petrochemical inputs are not separate from industrial strategy. They are the bloodstream of industrial strategy. Japan’s support for Vietnam’s crude supply is a useful start, but Tokyo should work with ASEAN on refinery resilience, fuel storage, emergency routing and electricity grid interconnection.
Third, Japan should use its credibility in infrastructure finance and industrial standards to help ASEAN move up the value chain. Resilience cannot mean simply relocating low-value assembly from one country to another. It must include technical training, supplier development, digital customs systems, clean energy infrastructure and capacity in critical mineral processing. Otherwise, ASEAN will remain exposed to the same external chokepoints, only with more factories sitting on top of them.
The risk is that Japan responds to the current crisis with tactical measures: more oil from the U.S., more stockpile releases, more bilateral memoranda and more defensive language around China. These may be necessary, but they are insufficient. Economic security cannot be built from emergency patches alone. At some point, the scaffolding has to become architecture.
ASEAN offers Japan that architecture. Its geography is not just a backdrop to trade. It is the operating system of Asia’s next phase of industrial resilience.
The Iran war has made clear that Japan’s vulnerabilities do not end at the factory gate. They run through sea lanes, ports, refineries, mineral flows, currencies and the political choices of partners. In that environment, ASEAN is no longer just Japan’s production base abroad. It is becoming central to Japan’s own economic survival.
Tokyo should act accordingly.
