Japan's new Emperor Naruhito succeeds father Akihito
Image copyright Getty Images Japan's new Emperor Naruhito is set to formally mark his ascension to the Chrysanthemum throne on Wednesday, a day after his father became the first emperor to abdicate in two centuries.
In his first act as emperor, he will inherit Japan's Imperial Treasures in a deeply symbolic ceremony.
The emperor in Japan holds no political power but serves as a national symbol.
Emperor Akihito, 85, who chose to abdicate due to his age and failing health, stepped down on Tuesday.
"I hereby pray for the well-being and happiness of our country and people of the world," he said in his final address.
The new imperial era "Reiwa", whose name signifies order and harmony, began at midnight local time, and will last as long as Naruhito's reign.
What will happen at the ceremony?
The Kenji-to-Shokei-no-gi - or Ceremony for Inheriting the Imperial Regalia and Seals - will begin at 10:15 local time (01:15 GMT).
Naruhito, 59, will receive three objects - a mirror, sword and gem - which are passed down through generations of emperors and are seen as the symbols of imperial power.
He will then give his first address as new emperor.
"In 1989 when Akihito [ascended the throne], he spoke about social welfare and peace," Ken Ruoff, director at the Centre for Japanese Studies at Portland State University, told the BBC.
These were goals that Emperor Akihito worked towards during his Heisei era, and his interactions with those stricken by disease or disaster endeared him to many Japanese.
"I think from Naruhito's first words, we'll have a good sense of what the new emperor's plans will be. I think it will set the tone [of the new era]," Professor Ruoff said.
Emperor Akihito took up the role of a diplomat during his reign, becoming an unofficial ambassador for Japan and travelling extensively to other countries, - something Naruhito is expected to continue.
What do we know about the new emperor?
Naruhito is Japan's 126th emperor. He attended Oxford University, and became crown prince at the age of 28.
In 1986, he reportedly met his wife, Crown Princess Masako Owada. at a tea party. They married in 1993.
Princess Masako later told reporters that she had accepted Naruhito's proposal after he said: "You might have fears and worries about joining the imperial household. But I will protect you for my entire life."
The princess, who reportedly suffers from a stress disorder, admitted in December that she felt "insecure" about becoming empress, but pledged to do her best to serve the people of Japan.
Masako was educated at Harvard and Oxford, and had a promising career as a diplomat before her marriage.
The couple's only child, Princess Aiko, was born in 2001. However, Japan's current law restricts females from inheriting the throne so she is not her father's heir.
Naruhito's brother Prince Fumihito will be next in line to the throne, followed by the new emperor's nephew, 12-year-old Prince Hisahito.
Why is the Japanese monarchy important?
It's the oldest continuing hereditary monarchy in the world. Legends date it back to about 600 BC.
In fact, Japanese emperors used to be seen as gods, but the country's wartime emperor Hirohito - Naruhito's grandfather - publicly renounced his divinity at the end of World War Two, as part of Japan's surrender.
The role was redefined by Emperor Akihito, who helped repair the damage to Japan's reputation after the war.
In 1991, two years after he ascended the throne, Akihito and the empress broke with convention and knelt down to speak to people affected by a volcanic eruption in Nagasaki. After the 2011 earthquake, tsunami and nuclear meltdown which killed thousands in eastern Japan, the former emperor and his wife Michiko were praised for reaching out to comfort survivors.
Their interactions with people suffering chronic diseases like leprosy, who have been marginalised in Japan, were also a sharp departure from the past.
Akihito will now be known as "Joko", which means "grand emperor", and by the English title "Emperor Emeritus", while Michiko will be "Empress Emerita".
