Japan seemed yesterday a nation filled with proud parents.

When the news leaked that Princess Masako might be pregnant, the usual harried expressions on Tokyo faces turned to beaming joy.

"It's fantastic news," said Yoshiko Suzuki, 50, a housewife from Chiba Prefecture, in town to have lunch with a friend.

Since her 1993 marriage to Crown Prince Naruhito, Japanese have kept an awkward silence about the failure of Masako, a Harvard-educated diplomat, to produce any offspring. Without an heir, what is billed as the world's oldest hereditary monarchy, stretching 2,600 years, seemed at a dead end with Naruhito, the son of Emperor Akihito.

But all was forgiven yesterday morning when the Asahi Shimbun newspaper quoted palace sources saying the princess, who turned 36 this week, was showing "symptoms of pregnancy." The Imperial Household Agency, which runs the palace and the lives of those within, said it would not confirm the report, but did not deny it, which was almost as good.

The bulletin was a happy jolt to a nation glum from news of tedious twitches in its moribund economy, of technological flops smudging its high-tech prowess, of sordid crimes.

So happy, in fact, that many Japanese said they do not much care if the baby is a girl or a boy. Technically, only a male heir can inherit the throne. But if it's a girl, people said, there is precedent to change the rules: Seven women have served as emperor, the last a mere 230 years ago.

"If it's a girl, the trend of society is that she will be the new woman emperor," said Toshiaki Kawahara, an industrious author who has squeezed out dozens of books about the imperial family. "The government would have to change the Imperial Household Law."

Since Akihito's father, Hirohito, gave up his role as a god and supreme authority after World War II, the role of the emperor has been reduced to symbolic appearances and glorified courtesies.

The imperial family has forgone the seemingly obligatory scandals of the British royals; the last racy gossip they produced was three years ago when the crown prince's brother denied he had a mistress in Thailand. While a majority of Japanese say they respect the tradition of the imperial family, most say they give the denizens of the palaces little thought--except when it comes to the matrimonial affairs of the crown prince and princess.

Naruhito was seen as a pleasant but uninspiring suitor, so there was some clucking when Masako Owada, a bright rising star in the Foreign Service, agreed to marry him. There seems little appeal to the job, which is mainly to avoid any gaffes and speak demurely. "The single most important task is to have an heir," said Kawahara.

When that job seemed to be left undone, there were worried whispers. The establishment press was too polite to mention it in all but the most circumspect ways. Only the weekly gossip magazines were rude enough to wonder in print whether the "problem" was Masako's or whether Naruhito, 39, was not up to the job.

So when Asahi, Japan's most respected and serious paper, trumpeted the Masako news as a big lead story yesterday, it rang true. Asahi distributed a free, rare "extra" edition, and the afternoon papers followed with identical front-page photos of the princess and triumphal headlines: "The Ring of Joy at the Imperial Palace . . . The Stork Flew With His Own Pace." The respected NHK television network added the details that the princess is five weeks pregnant, had morning sickness and is due to deliver Aug. 6.

It seemed a bit premature for Hitoshi Nakajima, 36, an office worker in Ginza. "Let's wait until her stomach gets bigger," he said.

But there was no denying the news touched many Japanese. "I feel sorry for the crown princess that such a personal matter is being discussed so openly," said Eri Sato, 30, a graduate student. But she acknowledged, "My father came to breakfast with a shy smile. He seemed to be as happy as if he was announcing that my younger sister was pregnant."

Special correspondent Shigehiko Togo contributed to this story.