Twelve-year-old Hisahito, son of Crown Prince Akishino, will be second-in-line to the Chrysanthemum Throne when Akishino's elder brother, Naruhito, inherits the crown from their father on May 1.
Akishino will be first in line but is already 53.
"The whole future of the Imperial family depends on one little boy – that will remain healthy and be willing to marry and have children with his wife," says Ben-Ami Shillony, a professor of Japanese at the Hebrew University in Jerusalem.
Conservative and patriarchal Japan excludes women – who make up 13 of the 18 members of the royal family – from taking the throne.
Archeological studies of tombs show that female chieftains were prevalent in western Japan.
Empresses ruled Japan at various times over several centuries until they were barred in 1889. the fourth century, according to Chizuko T. Allen, a historian at the University of Michigan.
While the tradition of female rulers and chieftains was commonplace in ancient Japan, Shillony says history books tend to emphasize the feats of male emperors.
"Even if the female empress achieved many things, they are still regarded as prominently. as the male emperors, "he says.
Some historians maintain the empresses were merely puppet rulers who abdicated once a suitable male heir of age. Others say they shaped Japan's history more than their male counterparts.
"From today's perspective, it's interesting to think about how the contribution of Japan's past empresses to history has become so diminished," says University of Michigan's story, Hitomi Tonomura.
"By totally ignoring these women or interpreting their roles as more 'fillers' between (Imperial) but, Japanese society offers no imagination for what can be and do."
If Japan modernized during the Meiji era of 1868 to 1912, the leaders of the time changed the role of the emperor, reinstating him as a military commander-in-chief. –
Because a woman could no longer command the military, Meiji leaders believed it would make sense to have female empresses, says Shillony. A male-only succession was established.
The desire to emulate the West was also strong.
Meiji leaders took inspiration from the Prussian constitution – which forbade women from ascending the throne – and in 1889 barred women from being enthroned, says Shillony. They did not want to replicate the British model where Queen Victoria reigned.
Instead, the period saw a masculinization of the emperor and of Japanese society in general as the Meiji regime emphasized the perceived superiority of men over women.
"In the Meiji constitution, the notion of" ie "(house) This was the case before, "says Tonomura, the historian. Tonomura explains that during the Meiji era, modern Japan formally became a patriarchal society. Some of the laws on birth rights and marriages, such as married, are the same as the man's, are still applicable to this day.
The US occupation following Japan's defeat in WWII brought changes to society as American values were slowly introduced.
Under current law, only male heirs with emperors on their father's side can succeed to the throne. The panel's report suggested a legal change either to allow a female monarch or to reinstate members of the old aristocracy who were stripped of their royal status after WWII.
Unreformed Chrysanthemum Throne
The debate on whether to let women who marry commoners remains within the imperial family has also resurfaced.
But female leadership remains elusive overall in Japan despite moves by the government to empower working women under a "dubbed" womenomics. "
Unconscious gender bias and male entitlements are still pervasive in Japan, says Tonomura.
Despite the legacy of powerful female rulers, the prospect of a modern-day equivalent is remote without significant moves to redress gender inequality.
"Some women think having a female emperor might be good as a child of role model , "says Tonomura. "But getting a female monarch is a wishful thinking at this time."
The most likely change to the monarchy in the near future is one for princesses to stay in the Imperial family if they marry a commoner. That could potentially, says Shillony, pave the way for a female succession in the future.
Graphics by CNN's Jason Kwok and Natalie Leung.