Japan's Prime Minister Shinzo Abe on Wednesday sent a ritual offering to a controversial shrine honouring World War II criminals that infuriates Asian neighbours China and South Korea.
Abe has not visited Yasukuni Shrine in person since December 2013 -- a trip that triggered a downturn in relations with Beijing -- and the premier is currently in Europe.
However, he sent a sacred "masakaki" tree bearing his name at the start of a four-day festival, a shrine spokeswoman told AFP.
There were no reports of members of Abe's cabinet visiting the shrine although some senior politicians also sent offerings.
The shrine honours 2.5 million war dead but also top World War II criminals and has frequently been a source of sour relations with countries that suffered from Japan's military atrocities.
Yasukuni has recently hit the headlines in Japan and internationally after its chief priest said he would resign after "highly inappropriate language" criticising the emperor was leaked to a magazine.
In a recent issue, the Shukan Post weekly magazine quoted chief priest Kunio Kohori, 68, as saying at a closed-door meeting in June that "the emperor is trying to destroy Yasukuni Shrine".
The more the emperor goes on memorial trips for the war dead, the more the shrine's position declines, he reportedly added.
Emperor Akihito has never visited since his coronation in 1989, while his father Hirohito did not return to Yasukuni after war criminals were enshrined there in the mid-1970s.
Akihito, who will abdicate next year, has throughout his reign hinted at pacifist views, which are sharply at odds with the aggressive expansionism Japan pursued under his father's rule.
Though he has no political power, the emperor has annoyed Japanese rightwingers by acknowledging that his country inflicted "great suffering" in China, and expressing regret over Japan's brutal rule of the Korean peninsula.