Networks broke in with special broadcasts, commuters snapped up extra editions of newspapers and political leaders rushed to offer congratulations on the birth of the long-awaited third in line to the Chrysanthemum Throne.

The boy is the first male child to be born to the royal family since his father Prince Akishino, the emperor's second son, in 1965.

For months, Japan's press was full of fevered speculation on whether it would be a boy or girl, although the palace insisted it had been a secret until the delivery.

Princess Kiko, an ever-smiling housewife just one week shy of her 40th birthday, had a smooth Caesarean section to deliver the boy, who weighed a light 2.6 kilograms (five pounds, 10 ounces).

"The new prince is very healthy and well. He has been crying," said doctor Masao Nakamura, who performed the Caesarean section operation at Aiiku Hospital.

"After the operation, I asked the princess, 'How do you feel? Congratulations.' And the princess replied to me, "Thank you. I feel well'," Nakamura told a press conference.

In the first of a series of rituals, Emperor Akihito sent his fourth grandchild a ceremonial 26-centimeter (10-inch) sword to symbolically protect him. The baby will be named in a week's time and is expected to be out of the hospital within 10 days."It is a wonderful thing that a baby was born. Preserving male succession is the foundation for Japan to keep its own traditions," said Nobuko Takemura, a 64-year-old housewife as she read a commemorative newspaper in downtown Tokyo.

Revelers toasted with sake and danced in celebratory red and white costumes in Tokyo's Mejiro neighborhood, where Kiko grew up in a middle-class apartment and met her husband in a bookstore as they studied at university.

The boy's birth could ease pressure on Crown Princess Masako, a former career woman who has suffered mental illness trying to adapt to the tradition-bound palace and produce a male heir to the throne.

Masako and Crown Prince Naruhito have one child, four-year-old Princess Aiko, in 13 years of marriage.

"I'm delighted today. I think Princess Masako will be relieved because Aiko will have the freedom to choose her life without worrying about suffering like her mother," said Teruko Den, 60, a housewife.

The surprise news that Kiko was pregnant more than a decade after her last child in 1994 was a dream come true for conservatives, who believe the monarchy has passed along a paternal line for more than 2,600 years.

Prime Minister Junichiro Koizumi, a reformist who steps down later this month, had supported introducing female succession, putting Aiko in line to the throne, an idea previously backed by a majority of the public.

But under pressure from the conservative wing of his Liberal Democratic Party, Koizumi dropped his proposed reform after news of Kiko's pregnancy.

Welcoming the royal birth, Koizumi said he still supported female succession in principle but would not press the case.

"I think it would be quite difficult to carry on imperial succession" unless the male-only rules are revised, Koizumi told reporters.

"It will depend on how future prime ministers think about the matter. But I don't believe it is a matter that should be taken to a parliament session next year."The front-runner to replace Koizumi, conservative Chief Cabinet Secretary Shinzo Abe, has criticized female succession in the past. He called yesterday for "caution" on the issue.