US President Joe Biden and Japanese Prime Minister Yoshihide Suga discussed the Senkaku/Diaoyu islands in a phone call. Here’s why

Among discussions about “global challenges” and “policy issues”, US President Joe Biden and Japanese Prime Minister Yoshihide Suga’s first conversation also turned to the topic of a small uninhabited island chain in the East China Sea.

While the five islets and three rocks covering just 7 square kilometres may seem insignificant, they have been quite a hot topic between US and Japanese officials.

In fact, Mr Biden and Mr Suga’s early morning call on Thursday was the third time in a week that the islands have come up in the first conversations between high-level ministers, with defence and foreign affairs officials in each country all weighing in on the topic.

Here’s why they keep coming up.

What’s the background?