Tokyo Report | Diplomacy | East Asia

Japan’s Iran Dilemma: Oil, Alliances, and Nuclear Double Standards

For Japan, the crisis is not only about energy security. It also strikes at the heart of the country’s moral and strategic identity.

An F/A-18E Super Hornet, attached to Strike Fighter Squadron (VFA) 14, prepares to make an arrested landing on the flight deck of Nimitz-class aircraft carrier USS Abraham Lincoln (CVN 72) in support of Operation Epic Fury, the U.S. strikes on Iran, Mar. 1, 2026.

The large-scale Israeli-U.S. military strikes against Iran that began on February 28 – notably killing Supreme Leader Ayatollah Ali Khamenei – have sent shockwaves far beyond the Middle East. For Japan, the crisis is not only about energy security. It also strikes at the heart of the country’s moral and strategic identity.

Japan depends on the Middle East for more than 90 percent of its crude oil imports. Any escalation that threatens shipping through the Strait of Hormuz therefore poses a direct economic risk.

Even before the attacks, oil markets were on edge. On February 27, U.S. benchmark West Texas Intermediate (WTI) futures closed in the low $67 per barrel range, while Brent crude settled in the high $72 range – both roughly seven-month highs. 

On March 2, oil surged the most in four years as the Middle East war all but halted shipping through the Strait of Hormuz. Brent crude jumped as high as about $82 per barrel and West Texas Intermediate approached $72 per barrel amid fears of prolonged supply disruption.

The immediate concern is not simply price volatility but the possibility of sustained disruption in Hormuz, the narrow waterway between Iran and Oman through which about one-fifth of global oil supply passes.

Following the strikes, Iran’s Islamic Revolutionary Guard Corps warned vessels against entering the strait. International media indicated that dozens of tankers altered course, while major Japanese shipping firms temporarily suspended passage. Although Japan maintains strategic reserves equivalent to roughly 240 days of consumption, a prolonged crisis would push up global prices and inevitably affect households and industry alike.

Against this backdrop, Tokyo has adopted a cautious diplomatic tone. Speaking before the Lower House Budget Committee on March 2, Prime Minister Takaichi Sanae stated that “Iran’s development of nuclear weapons can never be tolerated.” At the same time, she avoided explicitly endorsing or condemning the Israeli-U.S. operation, instead urging a diplomatic resolution. The calibrated ambiguity reflects Japan’s delicate position.

Japan is the United States closest treaty ally in Asia, yet it has historically maintained relatively cordial ties with Tehran. In 2019, then-Prime Minister Abe Shinzo visited Iran in an effort to mediate tensions between Washington and Tehran. Today, however, Tokyo’s room for maneuver is narrower. With a summit between Takaichi and U.S. President Donald Trump scheduled for March 19, alliance solidarity weighs heavily on the government’s calculations.

Yet the implications of the strikes extend beyond alliance management. They expose deeper contradictions in U.S. nuclear policy – contradictions that resonate acutely in Japan, the only........

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