Does a Strait of Hormuz blockade constitute a “life-or-death crisis” for Japan?

It is reported that Iran has blocked the Strait of Hormuz. This strait is crucial for Japan’s energy imports. The Japanese government has previously cited a “mine-blocked strait” as a hypothetical “life-or-death crisis” scenario that justifies exercising the right of collective self-defense. However, this time, the situation will be carefully assessed.

A “life-or-death crisis” is a concept defined in the security-related laws passed in 2015 during the Shinzo Abe administration.

A “life-or-death crisis” refers to a situation where another country with close ties to Japan is attacked militarily, creating a clear danger to Japan’s survival. If the Japanese government deems the situation serious, it can exercise the right of collective self-defense to a limited extent if no other appropriate means are available.

During the deliberation of security-related laws in the Japanese Diet, Abe cited a mine-blocked Strait of Hormuz scenario as a specific example of a life-or-death crisis. The mine-clearing (removal) of mines laid by other countries’ militaries as part of the exercise of force can be considered an exercise of force. Over 90% of Japan’s crude oil imports rely on the Middle East. It is estimated that 80% of the tankers transporting this crude oil pass through the Strait of Hormuz, located at the entrance to the Persian Gulf.

If the strait were blocked by mines or other means, it would severely impact Japan’s energy supply. The United States, an ally, might also seek Japan’s assistance in mine clearance.

The Japanese government at the time estimated that the likelihood of a mine clearance situation actually escalating was low. Prime Minister Abe also stated in parliamentary debate, “We are not specifically imagining that this situation would actually occur.”

There is no clear standard for classifying a situation as an existential crisis; the Japanese government must make individual judgments based on actual events. Prime Minister Sanae Takaichi explained at a House of Representatives Budget Committee meeting on March 2nd, “We are gathering information on the facts.”

Officials from the Japanese Ministry of Foreign Affairs believe that laying mines “would be antagonizing the world, and Iran is quite cautious.” Officials from the Japanese Ministry of Defense also believe the possibility is “low.”

To date, there have been cases in which the Strait of Hormuz has threatened resource imports, but the Japanese government has never invoked its right of collective self-defense. In 2019, a Japanese-operated oil tanker was attacked near the Strait of Hormuz. At the time, the Japanese government believed the attacker was unknown and there was no need to worry about energy supply disruptions, therefore it did not classify it as an existential crisis.

The potential blockade of the strait was also discussed in connection with a potential US attack on Iranian nuclear facilities in June 2025. Then-Prime Minister Shigeru Ishiba did not explicitly state whether it constituted an existential crisis.