How Iran War Is Quietly Destroying US's biggest ally i.e. Japan

When the United States and Israel started bombing Iran on February 28, 2026, the headlines, inevitably, were dominated by the Middle East. But it is likely no economies outside the region have felt the aftershocks more keenly than Japan.

Japan imports virtually all of its crude oil from Middle Eastern suppliers, delivered almost exclusively through a 33-kilometer choke point known as the Strait of Hormuz, which has been a no-go for commercial vessels since the war began.

Since May 2026, marine intelligence firm Lloyd’s List has logged virtually zero transmissions from Western-allied tankers proceeding through the chokepoint. Instead, in their stead, Iran’s Revolutionary Guards have reportedly instituted their own, unofficial, toll system for ships wishing to pass, demanding up to $2 million per vessel, paid either in yuan, bitcoin, or stablecoins-a startling example of the collapse of the established shipping order.

For an economy that has practically no reserves of its own, this disruption is not some abstract geopolitical inconvenience; it is a significant hit to input costs of manufacturing, transportation, agriculture, and household energy.

The Bank of Japan signals this damage with clearest institutional authority in its March monetary policy review,halving its growth forecast for the year to 0.5 percent while at the same time increasing its inflation forecast to 2.8 percent.

This combination-a slowing growth prospect combined with accelerating inflation-is the textbook definition of stagflationary policy impasse: If the central bank raises rates, it risks choking off what little economic momentum there is while fighting inflation; if it stays on hold, inflationary pressure may mount.

Independent modeling is aligned with the Bank of Japan’s cautious approach. Examining the likely course of the conflict, Nomura Research Institute’s chief economist Takahide Kiuchi models a protracted war and significant, but not complete, closure of the Strait shipping lanes, pushing the price of crude to $87 per barrel, reducing Japan’s GDP by an estimated 0.18 percent, and pushing up consumer prices by approximately 0.3 percent.

 

The conflict has already dragged out far beyond early expectations with a July ceasefire collapse after the bombardment of commercial vessels by Iran. In such context Japan is more likely tracking this base case than the scenario the country was hoping for weeks prior.

Markets have indeed priced in the strain; the yen has fallen to its lowest against the dollar in about 20 months, reaching close to and temporarily passing 158-159 against the dollar as higher energy costs and flight-to-safety dynamics pull investors away. “Significant volatility”, a particularly harsh phrase for a usually reserved Japanese Finance Ministry, has prompted Finance Minister Satsuki Katayama to indicate that her government may step into the currency market.

Equity markets have followed. In late March, for example, with nearly four weeks gone and no sign of a resolution, the Nikkei 225 fell 3.3 percent in a day and hit a two-month low amid a broad-based decline that spanned technology, financial and consumer names. Foreign investors, which had bought Japanese equities heavily through early 2026, are net sellers for the first time in approximately five months.

And the public has felt the pain. In mid-March, a survey by the Asahi Shimbun showed that 90 percent of respondents were at least ‘somewhat’ or ‘very concerned’ about the impact of the conflict on Japan’s economy-proof that a war taking place thousands of kilometers away is no longer just an issue for the financial pages and now affects daily household budgeting.

Sources: Nikkei Asia; Nippon.com (Japan Data, citing Nomura Research Institute); Axios; CSIS; Wikipedia (“Economic impact of the 2026 Iran war,” “2026 Iran war ceasefire”); Trading Economics; CNN; Britannica.