A laden supertanker linked to Japan appears to have completed a transit through the Strait of Hormuz, in what may be the first successful attempt by an oil carrier from the country to leave the Persian Gulf since the Iran war began.

The Idemitsu Maru began sailing late on April 27 toward the strait from northwest of Abu Dhabi, where it had been sitting idle for more than a week, according to tanker-tracking data compiled by Bloomberg. The tanker followed a Tehran-approved northern route near the islands of Qeshm and Larak and successfully cleared the strait on April 28, the data showed. 

The vessel is carrying 2 million barrels of crude, which was loaded from Saudi Arabia’s Juaymah terminal in early March.

The 2007-built Panama-flagged very large crude carrier had entered the Persian Gulf a few days before the U.S. and Israel attacked Iran in late February. It’s listed as being operated by the tanker arm of Japanese energy conglomerate Idemitsu Kosan Co., and is currently signaling Nagoya, Japan, as its destination with an estimated arrival on May 18.

A company spokesperson said that for safety reasons, Idemitsu would not comment on the status of individual vessels. 

Ship-tracking in the Strait of Hormuz may not accurately capture all transits as some vessels have transponders switched off, and signals in the region can be interfered with. 

A transit by a Japanese-owned tanker would be a shift in approach by the nation’s refiners and shipowners. Idemitsu Maru’s attempt is also noteworthy as it’s one of the largest tankers to do so since the U.S. began its own blockade of Iranian ships two weeks ago. During that time, traffic through the strait has remained near zero.

While Japan is heavily dependent on Middle Eastern crude, its shipowners have been cautious amid the hostilities. Idemitsu, among other refiners, has relied on ship-to-ship transfers to procure some cargoes, with these taking place well outside the Persian Gulf. They have also turned to buying alternative supplies from the U.S. carried on smaller tankers.

Some Japan-linked vessels have made the transits during the war, although they were limited to cargoes of other commodities. Earlier this month, a liquefied petroleum gas carrier co-owned by another Japanese shipowner made the exit in a passage that was facilitated by India.