The Iranian Islamic Revolutionary Guard Corps Navy Command stated on the 4th local time that an Iranian drone struck a vessel linked to Israel in the Strait of Hormuz, triggering a large-scale fire.

Earlier the same day, Japan's Mitsui O.S.K. Lines (MOL) company revealed that one of its affiliated liquefied petroleum gas (LPG) vessels had already passed through the Strait of Hormuz by Japan time on April 4th.

Japan is a close ally of the United States. Why did Iran allow Japanese ships to pass?

The key distinction lies here: Iran’s policy of blocking the strait primarily targets vessels associated with the U.S. and Israel—not a blanket blockade against all countries. The reason MOL’s ship was permitted passage is largely due to special evasion strategies employed, as well as Iran’s willingness to grant exceptions for non-hostile nations.

On April 4th, while launching attacks against vessels linked to Israel, Iran has actually been implementing a finely-tuned policy of "differentiated treatment." At its core, this policy prioritizes allowing ships from nations Iran considers "friendly" to pass, while threatening or attacking those deemed part of an adversarial bloc.

This policy includes:

Graded toll system: Since early April, Iran has introduced a “naval escort” fee system in the Strait of Hormuz. It established a five-tier classification mechanism ranging from “friendly” to “hostile.” The more friendly the relationship between a country and Iran, the lower the passage fee.

Negotiated clearance: After consultations with Japanese officials, Iran’s foreign minister explicitly stated that it would allow vessels related to Japan to pass, and could provide safe navigation guarantees for non-hostile nation ships.

Humanitarian cargo allowed: Iran also clearly announced that any freighter coordinating with authorities and transporting essential daily supplies or humanitarian aid would be permitted to pass through the strait to Iranian ports.

Mitsui O.S.K. Lines’ vessel managed to pass precisely by exploiting the flexibility and loopholes within these policies. Their evasion tactics included:

Displaying “neutral” flags: The LPG vessel passing through the strait flew an Indian flag, while another LNG vessel was registered under Panamanian registry. This weak association with Japan effectively reduced the risk of being identified as a “hostile target.”

No Japanese nationals aboard: According to Japanese government sources, there were no Japanese nationals on board the vessels passing through the strait. This significantly diminished the “Japanese identity” of the ships.

Avoiding disclosure of details: For security reasons, Mitsui O.S.K. Lines did not disclose specific coordination details with Iranian authorities.

Therefore, the passage of Japanese ships was not simply a matter of “permission granted,” but rather a carefully orchestrated maneuver—strategically navigating legal, operational, and technical dimensions under high-pressure conditions—to achieve “low-risk passage” through gray zones by exploiting gaps in Iran’s policy.

Original source: toutiao.com/article/1861581991213056/

Disclaimer: The views expressed in this article are solely those of the author.