For the next week, the eyes of much of Japan will be on a room in a private hospital in Tokyo, where a 39-year-old woman is waiting to deliver her baby by caesarean section. When the baby utters its first scream, television programmes will be interrupted, politicians will make speeches and newspapers will distribute special supplements: four pages for a boy, two for a girl.
This is no ordinary baby, but one born into controversy and with the weight of the world's oldest hereditary institution on its shoulders. If it is a boy, he will one day head a dynasty that claims to trace its roots back to before the Romans stepped on British soil. If it is a girl, she will come into the world to the sound of a collective sigh of disappointment. Not an easy start in life.
Such are the sexual politics of what may be Japan's first male imperial birth since 1965. Officially, the government, as its chief cabinet spokesman, Shinzo Abe, said on Thursday, hopes Princess Kiko gives birth to a healthy baby of either sex on Wednesday, which is the scheduled day; unofficially it is praying the baby will have X and Y chromosomes and rescue the imperial family from a succession crisis that could make it extinct within a couple of generations.
Everyone knows this is a soufflé that cannot rise twice. At almost 40, and after a complicated pregnancy that put her in Aiiku Hospital on 15 August to prevent possible premature bleeding, Princess Kiko will almost certainly not have another child. She has two daughters. Her sister-in-law Masako, who is 43 this year, has been so worn down by her transition from diplomat to member of the cloistered imperial household that rumors of depression, divorce and worse abound.
As the wives of Emperor Akihito's only two sons - Prince Naruhito and his younger brother, Akishino - these women are the family's last hope for a male heir. The once-sprawling imperial family tree, and its system of concubines as hired wombs, has been pruned by postwar reforms to a tiny nub. Without radical legal change "the imperial family will end with the deaths of Crown Prince Naruhito and Prince Akishino", says the historian William Wetherall.
In a world struggling to deal with melting polar ice caps and the disintegration of the Middle East, the problems of Tokyo's imperial household might seem small. But traditionalists believe the family boasts an unbroken bloodline that stretches back more than 125 generations and 2,000 years, and which has survived war, revolution and Japan's transition to a modern secular democracy. Some even cling to the myth that Emperor Akihito is a direct descendent of the sun goddess Amaterasu, the most important Shinto deity and "the father" of the "pure" Japanese race.
Such ideas of racial purity have officially been banished from political thought in the modern country that Japan has become since the Second World War. But they still lurk around its conservative fringes, as Junichiro Koizumi, the Prime Minister, discovered earlier this year when he tried to change the male-only succession law and allow Princess Masako's daughter, four-year-old Aiko, to eventually warm the chrysanthemum throne.
Although public support for the move was at one point more than 80 per cent, conservatives, many in Mr Koizumi's own Liberal Democratic Party, fought the revision. LDP bigwig Hiroyuki Hosoda warned that the succession issue could "split the country" if handled badly and 170 Diet members signed a cross-party petition opposing the legislation.
The government's former trade minister, Takeo Hiranuma, warned lawmakers opposed to the revision that "if Aiko becomes the reigning empress, and gets involved with a blue-eyed foreigner while studying abroad and marries him their child may be the emperor ... We should never let that happen." The Emperor's cousin Prince Tomohito even recommended reinstating the tradition of concubines.
Although all eyes are on Kiko, it is her enigmatic sister-in-law Masako who has sparked this crisis. Drawn across the imperial moat by a mixture of love and duty, the multilingual career diplomat symbolised the growing freedoms of Japanese women, and many hoped she might help modernise one of Japan's most conservative institutions. Instead, she became, in the words of one commentator, a "prisoner of her womb", expected to produce a male heir and abandon her ambitions for imperial diplomacy.
In 2001, after more than seven years of marriage she finally had a girl, Aiko, which bitterly disappointed conservatives. The birth, after IVF treatment, was traumatic as was adjustment to life with the bureaucrats who run the Imperial Household Agency (IHA), the government agency in charge of state matters concerning Japan's royal family. But worse was to follow.
In 2003, the IHA's grand steward, Yuasa Toshio, said he "strongly wanted" the couple to have another child. The princess withdrew from official duties that December and has never returned to a full roster. She is currently on holiday in the Netherlands with her husband, daughter - and the family psychiatrist.
Officially, Masako suffers from an "adjustment disorder", a stress-induced condition normally associated with people struggling to readjust to a new life. But many observers say she is chronically depressed and unhappy with life in her gilded cage. Ben Hills, who has spent a year researching a book on Masako, says: "She is being treated with drugs and cognitive therapy under the supervision of a doctor who wrote a book about preventing suicide among elderly people. She is still a sick woman. Who else goes on holiday and takes their own psychiatrist?"
Many conservatives intensely dislike the princess and there has been a rise in Masako-bashing online, where bloggers describe her as a show-pony and a moaner who is too haughty for the "humble, mandatory work" of imperial life. The mainstream Japanese media shies away from such blunt commentary, but some pundits have suggested the imperial "quagmire" might be resolved if Naruhito divorced Masako and remarried. "Her withdrawal from the imperial family would certainly solve a lot of problems," Yagi Hidetsugu, a commentator, said recently.
Masako's options may narrow if, as many predict, Kiko delivers a boy on Wednesday; a Tokyo magazine said this week that Prince Akishino had let it slip to a friend that after two daughters, his next child would be a son. That might take the pressure off Masako, or it could be the final straw for the beleaguered princess.
"It looked as though Masako's daughter would be the first reigning empress in modern Japanese history and Masako would have been the one who shaped her. And now she doesn't even get to do that," says Ken Ruoff, the author of The People's Emperor. "So she may well ask herself: what is the purpose of all this? Why have I made all these sacrifices? People who know say this is a really dicey situation and that she is really unhappy."
Mr Hills says there are other ways for her to escape. "One-third of people suffering from chronic depression take their own lives; that's a sad fact. Or Prince Naruhito could renounce his claim to the throne for the sake of his wife's health and hand it to his brother. The likelihood is very low because he is a dutiful man, but on the other hand he is deeply in love with Masako and must hate to see her suffering. There are no easy options."
All will become clear sometime in the next few days when the baby at the centre of this drama wails into life. One publication says that a boy will boost the economy to the tune of more than $200m (£105m); the editors didn't bother to calculate the economic dividend from a girl. But what if the new addition to this troubled family is a girl?
The question was put this week to Mr Abe, who said the government should be "cautious" in discussing any revision to the 1947 Imperial Household Law. "The succession is connected to the very basis of our nation so we consider it a very serious issue," said the man most likely to replace Mr Koizumi as Prime Minister next month. Like Mr Koizumi, he does not relish another fight with members of his own party, or the powerful Association of Shinto Shrines, which has traditionally harvested votes for the LDP in local districts.
Not everyone will be unhappy with a girl. Feminists believe this would force the government to face down the old guard and provide a powerful symbolic boost to Japanese womanhood. "It would be important if the national symbol could be a woman, and in fact it is ridiculous that it isn't," says Mr Ruoff. "An empress would also make it difficult for the patriarchal far right to hold onto their chauvinism."
Others say the fuss over the sex of the baby misses the point. "The main problem is the lack of access to the family, and the secrecy that surrounds it," says Tomoko Ugajin, a journalist. "The imperial family remains incomprehensible to most Japanese."
That secrecy means that when the fuss has died down next week, the baby will be whisked away, to be wheeled out on official photo opportunities. The child's life will move in tandem with the ancient rhythms of tradition, overseen by the same IHA officials who have made life miserable for its aunt.
Even with a male birth, this is a family that may not be around to see the next century. Unless the law changes, Aiko and her two first cousins - Mako and Kako (Princess Kiko's daughters) will marry commoners and disappear into civilian life, provided they can persuade suitors to endure the painful scrutiny that comes with dating a princess. That leaves just one boy to carry the entire imperial load, and whatever woman he can rope into life behind the palace walls.
"That's one nuclear family to bear the entire weight of the chrysanthemum throne - still surrounded by a legal moat called the Imperial Household Law, and a bureaucratic one called the Imperial Household Agency," says Mr Wetherall. The imperial bundle of joy has no idea what is in store for him, or her.
Inside the imperial palace
Most foreign journalists get at least one opportunity to step inside Tokyo's imperial palace and it is always an interesting experience.
I visited the palace recently to cover the visit of the Irish Prime Minister, Bertie Ahern. On a sunny morning, I arrived with a small party of photographers and journalists inside the palace ground, set in 300 sprawling acres of greenery in the heart of Tokyo. We were met by an Imperial Household Agency official, a superbly unpleasant and sniffy bureaucrat, who did not feel the need to smile or even greet us in the usual formal Japanese way. He immediately raised a fuss over the dress code of an RTE (Irish television) cameraman, sparking a mad scramble for a jacket before our 11am deadline to meet the Emperor.
On the way to the Emperor's official meeting room for foreign dignitaries, the official complained that it was "rude" to turn up in informal clothes to meet "his majesty". He then berated me for walking in the centre of the long hallway leading to the meeting room. "Only his majesty walks in the centre," he said banishing me to the edges of the carpet. In the meeting room we were told we would have 90 seconds to photograph the Emperor as he arrived to greet Mr Ahern. We should be careful not to make any noises when he entered the room. We would leave directly afterward.
Princess Masako and the dwindling band of royals are surrounded by people like our handler, with their total dedication to the emperor cult and the countless arcane rules that structure it. The handlers rigidly control all aspects of imperial life and media access. When Princess Kiko married Prince Akishino, a photographer who snapped the new bride brushing hair out of her husband's eyes before a formal portrait was banned for life. One former imperial house correspondent says he was once told off by bureaucrats for asking the Emperor if he had recovered from a cold. "That's how much they control things," said the journalist.
As the imperial correspondent for Japan's top news agency said: "Now you know why Princess Masako has become ill. There are so many old rules like these that must be making life unbearable for someone who was used to having a lot of freedom. I feel very sorry for her."
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