Beyond the material trappings that accompany what the Japanese claim to be the world's oldest continuous hereditary monarchy the new emperor will receive a more important inheritance: the deep and abiding respect his father Akihito has accumulated over his three-decade reign.

Akihito went through his abdication rituals on Tuesday ahead of handing over the throne to Naruhito at midnight.

Replicating his father's bequest on his own will be Naruhito's greatest challenge.

The love many in Japan feel for 85-year-old Akihito was on display when he made his last official visit to the winter sumo tournament earlier this year. A huge crowd of people leapt to their feet, whooping and smiling as they held up babies and waved flags.

This outpouring of emotion, however, was earned through much smaller moments, such as his visit in 2011, wearing a windbreaker instead of his usual bespoke suit, to comfort victims of a massive earthquake, tsunami and nuclear meltdowns.

Entering a Tokyo shelter where evacuees were living, he knelt on the wooden floor and listened to the stories of survival and devastation.

Akihito has no political power under the postwar constitution, and his official duties are heavy on photos, ceremonial visits and foreign trips, his every public move stage-managed by an aggressive and controlling Imperial Household Agency.

Yet, through his dogged outreach to his subjects in Japan, and his expressions of remorse to people in parts of Asia where his father's troops once rampaged, he has redefined the role of emperor and, in the process, made himself much more popular than any elected politician.

"Akihito is leaving some big shoes to fill for Naruhito," said Jeff Kingston, director of Asian studies at Temple University in Japan.

"Akihito has opened the door, and Naruhito seems well placed to continue the work. The problem is you have to earn the moral authority; you're not given it."

Since Akihito took the throne after the death of his father, Hirohito, in 1989, his rule has in many ways been an attempt to come to terms with his father's much darker legacy.

Hirohito spent the first part of his long reign revered as a divinity; he ruled the next four decades stripped of his former powers, a less-than-enthusiastic figurehead who seemed at times bewildered by an economic boom that transformed Japan into a global force by the 1980s.

Akihito's abdication, planned since at least 2016, will ensure a smoother succession for Naruhito. But it's his blueprint for how to be a successful figurehead emperor that may be his best gift to his son.

It has seemed, at times, like Akihito has been on one long tour, ministering to his subjects time and again after a string of natural disasters, of which Japan is a global leader, and championing, among others, leprosy patients, the elderly and the disabled.

And he has visited World War II battle sites, including Okinawa and the Pacific island of Saipan, to pray for the dead on both sides and express his remorse for the war.

A parade of more cautious, little-loved political leaders, by contrast, has tended to shy away from addressing the historical scars of the war.

Naruhito's struggle will be to now try to make the same connections his father mastered over the decades.

It will take work. For while there is strong public support for the imperial institution, it is not universally loved.

Many young people just aren't interested. On the left, there's often embarrassment that the country still maintains such an antiquated, socially elevated figurehead. And right-wingers have often found themselves (respectfully) cringing at Akihito's seemingly liberal inclinations.

Naruhito seems able to laugh at himself: In his memoir, recently republished in English, of his time studying at Oxford in the early 1980s he writes of almost flooding the student dormitory where he lived because he'd never done laundry before.

Naruhito, when he's invested with the sacred imperial regalia on Wednesday, will become a living link to millennia of history, myth and tradition, a bridge to both the nation's ancient past and its uncertain future.

For many, the throne represents a comforting symbol of nation, identity and stability in a constantly shifting world.

"Change is not always a good thing," said Daniel Sneider, a Japan expert and lecturer at Stanford University.

"Sometimes the retention of social institutions and traditions is what preserves a society. The imperial institution lends a sense of dignity and civility to Japanese life ... and the Japanese often look to the institution for that sense of themselves."

Australian Associated Press