Lawmakers kicked off discussions on Friday about possible relaxations of the imperial family's strict succession rules, although women will likely remain barred from the Chrysanthemum Throne.
The imperial family has a myth-filled history dating back more than 2,600 years, but Japan currently has only one heir: Emperor Naruhito's 17-year-old nephew Prince Hisahito.
Naruhito's only child, Princess Aiko, 22, cannot succeed her 64-year-old father due to male-only succession rules.