Japan's Princess Kiko gave birth on Wednesday to a baby boy, the first imperial male heir to be born in more than four decades and the answer to the prayers of conservatives keen to keep women off the ancient throne.
TV programmes flashed the news that a male heir—the third in line after his uncle and father—had been born, although tabloid media had forecast weeks earlier that the baby was a boy.
Newspapers issued extra editions, eagerly snapped up.
Royal fans waving Japanese flags and shouting "Congratulations" greeted Emperor Akihito and Empress Michiko, as the beaming grandparents left a hotel in Sapporo, northern Japan, where they are on an official visit.
The birth will scuttle for now a plan to let women ascend the throne, an idea opposed by conservatives eager to preserve a tradition they say stretches back more than 2,000 years. But with many Japanese in favour of reforms, debate may not be over.
Chief Cabinet Secretary Shinzo Abe, a conservative expected to become Japan's new prime minister this month, welcomed the birth. "It's a refreshing feeling that reminds us of a clear autumn sky," he told reporters.
Asked about the succession law reform, he added: "It is important for us to discuss it calmly, carefully and firmly."
An Imperial Household Agency official told reporters Kiko had given birth by a Caesarean operation to the 2,558 gram (5 lb 10 ounce) boy at 8:27 am (2327 GMT).
He said both Kiko, 39, and the baby were doing well.
No imperial boys had been born since the baby's father, Prince Akishino, in 1965, raising the possibility of a succession crisis. Crown Prince Naruhito, 46, and Crown Princess Masako, 42 have one child, 4-year-old Princess Aiko.
Japanese emperors have not been worshipped as gods since Akihito's father, Hirohito renounced his divinity after Japan's defeat in World War II, and have no political authority.
But the monarchy remains rich with symbolism and ritual.
Near Tokyo's Gakushuin University, where Akishino and Kiko met, a dance troupe performed, carp streamers flew in honour of the infant boy, and locals toasted the baby with sake rice wine.
"It's good that a boy was born so that the royal family could keep its male lineage. I'm happy that Japan's tradition has been maintained," said Tadayuki Aman, a 77-year-old doctor.
Later in the day, the infant was to receive a ceremonial sword from the emperor. Akishino will choose his son's name a week later.
The birth took place at the private Aiiku Hospital, which has close ties to the royals and has seen many celebrity births.
Prime Minister Junichiro Koizumi had planned to revise the law to let women ascend the throne but Kiko's pregnancy put on hold that proposal, which would have cleared the way for Aiko to become Japan's first reigning empress since the 18th century.
Most Japanese, however, favour giving women and their children equal rights to inherit the throne and on Wednesday many said the birth of a boy should not derail reform.
"Other countries around the world have female monarchs. Japan should also change with the times," said Masashi Yamaguchi, a 25-year-old IT engineer.
Experts agree reform of the succession law will be needed eventually, despite the birth of the boy, since ensuring male heirs is difficult without a royal concubine.
The practice of emperors taking concubines ended when Emperor Akihito's late father, Hirohito, refused to take one.
The birth is the latest chapter in a drama that began more than two years ago when Masako, a Harvard-educated former diplomat, developed mental illness caused by the stress of rigid royal life, including pressure to bear a son.
Some Masako fans hoped the baby's birth would ease her plight. "This might take the burden off her to have a son or to raise her daughter to be emperor," said Masae Tone, 76, a former high school English teacher.
Japan has had eight reigning empresses but conservatives stress they were stop-gap rulers.