For 28 years, Emperor Akihito has been a steady and reassuring presence in Japan, a fact that many people here are reminded of on a daily basis. After all, 2016 is officially known as “Heisei 28,” marking Akihito’s time on the Chrysanthemum Throne.

But now, the 82-year-old “emperor for life” is laying the groundwork to relinquish his role and pass it on to his oldest son, Naruhito. That will be tricky. Not only is there no legal provision for him to abdicate, but even raising the prospect of it could be unconstitutional.

“Under the current law, he can’t abdicate, even if he wants to. There is no option but to carry on,” said Yasushi Kuno, a veteran journalist who covered the imperial family for the Nippon television network for years.

Akihito is scheduled to make a prerecorded video statement to the Japanese people Monday afternoon, during which he probably will say that he is having difficulty carrying out his official duties.

He has had health issues — prostate cancer and heart problems — and, marking his birthday in December, he said there had been times when he had felt his age.