Asked if Japan was considering retaliatory measures, top government spokesman Yoshimasa Hayashi said the two nations would continue to discuss details of the duties, which came into force at midnight US time (4am, Wednesday).

“Widespread measures to limit trade risk having a significant impact on the Japan-US economic relationship as well as the world economy and multilateral trade system,” Hayashi told reporters.

“That Japan was not excluded from the imposition of additional tariffs is regrettable,” he said.

Japan exported 31.4 million tonnes of steel in 2024, of which 1.1 million went to the US – around 4% of the country’s steel imports, according to Washington.

“Imports of Japanese steel and aluminium products won’t harm US national security, but rather, our high-quality products are difficult to replace and essential to strengthening the competitiveness of the US manufacturing industry,” Hayashi added.

Economy, trade and industry minister Yoji Muto said in Washington this week he had asked US officials to exempt Japan from metal and upcoming vehicle tariffs.

“During minister Muto’s US trip, Washington expressed its position that it considers its relationships with Japan a priority, and that Japan’s investment in the US as well as the role it plays in the US economy such as through employment are valued,” Hayashi said.

Masakazu Tokura, chair of the , said earlier this week that “the proportion of Japanese exports of steel and aluminum to the US… is very small, so the direct impact on Japanese companies will not be that great”.

However, “tariffs on vehicles will have a significant impact”, especially since many Japanese companies have expanded into Mexico and Canada, and are exporting to the US from there.

“The biggest problem of all is the decline in predictability for business, which may make companies ‘hesitant to invest’,” Tokura added.

Japan is home to the world’s top-selling carmaker Toyota, and the health of the auto industry impacts many sectors, from parts manufacturing to steel and microchips.

Of the country’s ¥21.3 trillion (US$145 billion) of US-bound exports in 2024, cars and other vehicles accounted for roughly a third.