When China broke out one of its “big guns” in last year’s trade war with the US – an array of export controls on rare earth elements – it helped spur a temporary truce in the pitched conflict between the two economic superpowers.

After Beijing’s announcement, many around the world expressed shock at the size and scope of China’s response to Washington’s sky-high tariffs. But for Japan, a squeeze on rare earth shipments was not so novel a concept.

In 2010, following the collision of a Chinese fishing trawler with Japanese patrol boats near the disputed Diaoyu Islands and the detention of the trawler’s captain, Beijing threatened “severe countermeasures”. Some Japanese businesses began to report their supplies of the critical minerals, largely sourced from China, had slowed or stopped entirely.

And while Beijing was adamant it had not enacted a ban or restriction on rare earth exports to its neighbour, prevailing perception in Japan was that China had carried out an unofficial cutback on shipments – a stance given credibility by a broader reduction in rare earth exports which had taken effect earlier in the year.

Now, with relations between Beijing and Tokyo at another low point, Japanese industries dependent on the minerals again fear their shipments will be delayed or halted.

Substantial bilateral channels have yet to be formed to address specific commercial and trade concerns, analysts and observers said, despite the two nations continuing to maintain a certain framework for diplomatic dialogue, including at the leader and ministerial levels.

“In the field of critical minerals, including rare earths, there is a growing perception that practical communication regarding export controls and licensing procedures has become less transparent than before,” said Kunihiko Shinoda, a professor at the Tokyo-based National Graduate Institute for Policy Studies (GRIPS).