Japan is facing a succession crisis, not for political leadership, but at the Imperial Palace, where there is a dearth of male heirs for the Chrysanthemum Throne. The situation has ignited a national debate over whether it might again be appropriate to have an empress on the throne.
The last time a woman reigned over Japan was January 9, 1771, when Empress Go-Sakuramachi abdicated after nine years on the Chrysanthemum Throne to make way for her sickly 12-year-old nephew.
Japan has always preferred having a male sovereign: including Go-Sakuramachi, only eight women have sat on the throne in 2,000 years of imperial history. A law passed in 1947 limits candidates to a male descendent of an emperor.
However, if Japan wants to retain its imperial bloodline, a woman might have to take the reins of the world's oldest continual monarchy again. For no male heir has been born into the royal family in 42 years.
Lawmaker Yoichi Masuzoe of the governing Liberal Democratic Party is among those who support the idea of changing the rules.
"Imperial family and [the] imperial system is in crisis. We have to make haste - very rapidly," Masuzoe said.
The reigning emperor, Akihito, 72, has two sons and a daughter, and the two males are eligible for the throne under the current system.
But the older son, Crown Prince Naruhito, and his wife have one daughter, and it appears unlikely they will have another child. Naruhito's younger brother, Prince Akishino, is the father of two little girls.
It was announced that Prince Akishino's wife, Princess Kiko, is pregnant. If she gives birth to a boy, the succession problem is solved for the moment. But if she has another girl, there will be no males in the next generation eligible to become emperor.
In previous times, an emperor would turn to concubines if necessary to ensure male offspring. But that option is deemed unseemly for the 21st century, and would very possibly be opposed by Emperor Akihito's two modern daughters-in-law, who both come from commoner stock.
There is one other eligible, but little-mentioned royal male. Prince Katsura, 58, is a cousin of the current emperor. But he has never married and has been wheelchair-bound since suffering a serious stroke in 1988.
Repeated surveys indicate strong public support for an empress, in part because of the popularity of the young princesses.
Democratic Party President Seiji Maehara, the leader of Japan's political opposition, also thinks the time is right to change the succession law.
Maehara says it appears difficult to maintain the patrilineal system without resorting to concubines, so an empress is probably unavoidable in the future, and thus changes need to be made to allow a matriarchal line.
That argument does not go down well with Takeda, 30, no neutral observer of the controversy. Takeda is a great great grandson of the Emperor Meiji, the great modernizer who died in 1912. Takeda is also a member of one of 11 aristocratic families stripped of regal status by the U.S. occupation following Japan's defeat in World War II.
Takeda rejects all the arguments for a matrilineal line, saying historical precedent was for women to act only as regents until a male from the imperial bloodline could assume the throne.
Takeda, a scholar of imperial family history, points out that an empress would have a difficult time presiding over hundreds of annual Shinto ceremonial duties, which hark back to the pre-war era, when the emperor was considered divine.
Takeda says those who are in mourning, have recently given birth or are menstruating are barred from entering holy places, meaning an empress might not be able to conduct numerous Shinto rites.
Takeda is author of a book entitled The Untold Truth of Imperial Family Members. He says the ultimate solution is to restore the branches of the royal family, such as his, that were cut off in 1945.
Proponents of the plan say that would ensure that the Japanese imperial bloodline's "Y" chromosome, which only males carry, would be transmitted to subsequent generations of emperors, maintaining the unbroken line stretching back into antiquity.
Liberal Democratic Party politician Yoichi Masuzoe says Takeda's proposal is ridiculous, because it would favor former aristocrats, many with tenuous blood links to long-ago emperors, over contemporary female descendants of recent sovereigns.
"As far as I know only one man would like to come back," said Masuzoe. "But if he traces back to the Imperial Family -- [it's] 600 years. The current emperor, Showa Emperor, Taisho Emperor, Meiji Emperor -- they worked very hard and they're really the cornerstone of our culture and our civilization. You abolish this to return some family relatives of long, long distant relatives? Personally, I cannot do that."
Prime Minister Junchiro Koizumi, as part of his sweeping reforms, had vowed to push through a bill allowing a woman to ascend to the throne. But news of Princess Kiko's pregnancy has put that political process on hold.
Princess Kiko is due to give birth in September, about the time Mr. Koizumi intends to step down, leaving the prime minister's successor to grapple with this sensitive issue. The eventual resolution will have serious ramifications for Japan's self-identity.