By Chris Hogg
BBC News, Tokyo
So the rumours were right. Princess Kiko was carrying a boy after all.
She has produced the first male heir to the Japanese throne in 41 years. The succession is assured.
Controversial plans to revise the Imperial Household Law to allow female members of the imperial family to accede to the Chrysanthemum Throne can now be sealed up and stuffed in the drawer for another few years, can't they?
The imperial birth will not put an end to the succession debate
That is what some of the more conservative members of the Imperial
Household agency will be hoping.
When Japan's outgoing Prime Minister Junichiro Koizumi proposed the change to the law last year, he was opposed by conservative elements in his own party as well as in the opposition.
While opinion polls suggested that more than two-thirds of the country saw little problem with women ruling as empresses in their own right, a vocal minority, including quite a few politicians from his own party, made clear that they were very unhappy with the plans.
So it is little wonder that within hours of the birth, the politician widely expected to become Japan's next prime minister, Shinzo Abe, seemed more at ease exclaiming in unusually florid language his reaction.
"It feels refreshing like the clear skies of autumn," he said.
He talked about the need for a calm and cautious debate, which some commentators interpreted as a resounding "no".
But the arrival of a baby boy has not "solved" the succession crisis. What it has really done has bought the imperial family some time.
Currently only males can ascend the Japanese throne
Emperor Akihito has two sons, Naruhito and Akishino
If Naruhito died without a male heir, Akishino succeeds
His baby son, so far unnamed, becomes third in line
Princess Sayako married a commoner so her children cannot ascend throne
The argument over whether or not women were suitable candidates to head the imperial family was distasteful to some because judgements were being made about whether individuals - the young princesses - who were already in the public eye were suitable candidates to rule as empress.
So now some experts say there is an opportunity to make it less personal.
It is better to have the argument now about how the rules could be changed in the future, perhaps for the children of the little boy born on Wednesday, rather than discussing whether this princess or that prince would make a better head of the imperial family.
Some argue that in fact the biggest problem facing Emperor Akihito and his offspring is not the succession crisis, but an increasing detachment between the monarch and his people.
Young people in Tokyo were pleased for the princess and her husband on their auspicious day, but they did not seem to have strong opinions about whether or not men or women should accede to the throne.
"I'm very happy," said Takashi Suzuki, who was shopping in the Marunochi district of Tokyo, "but I don't care about the succession."
"If it had been a girl," said Steve One, "it might have strengthened the debate, but now it's a boy, they may as well forget about it".
Only Mamiku Shomitsu had more to say on the succession issue.
"It's a very delicate situation. Many people would like Crown Princess Masako's daughter to be empress. Women should be able to accede to the throne like in Britain."
Of course on days like this, there is intense media interest in the imperial throne. But many Japanese have more prosaic concerns - growing inequality in society or a perceived lack of job security.
The trials and tribulations of those "trapped in the gilded cage", as the imperial family is sometimes styled, may not be so important to them as it might have been to their parents.
"Why not give them the same options as any other family?" asks Mariko Fujirawa, a social commentator.
"Other families can adopt, or their daughter's husbands can take their new wife's family name, or they simply abandon the aspiration for an unbroken male blood line. To ask them to go on producing male heirs is unrealistic."
Status quo likely
The current emperor's great-grandfather produced five sons. But he managed it because he had five concubines.
For generations that was how the imperial family made sure they produced enough males to keep the lineage unbroken.
But this is not really a realistic option for the 21st Century, and the emperor's father, Hirohito, refused to take a concubine.
So will the other option, allowing women to accede to the throne eventually be forced through instead?
Not in the near future.
The decision will be down to politicians and it is the kind of issue that has the potential to lose more votes from die-hard traditionalists than win support from modernisers.
With a difficult election ahead of them next year, the ruling Liberal Democratic Party is unlikely to want to take on the forces of conservatism - as good an argument as any for preserving the status quo.