The last emperor to abdicate was Emperor Kokaku in 1817 in the later part of the Edo Period, and the royal male line is unbroken, records show, for at least 14 centuries.
Added to the abdication bill is a draft resolution that potentially questions whether women who marry outside the family have to rescind their royal rights.
Currently, imperial law also decrees that — unlike in Europe or Great Britain — any princess who marries a commoner must leave the family.
The latest case of Princess Mako, who last month revealed plans are underway for her to become engaged to law firm worker Kei Komuro, once again drew the topic into the limelight.
Mako is one of 14 women in a royal family of only 19 people.
In addition to Princess Mako, there are six other unmarried princesses who could lose their imperial status if they marry commoners, raising the …