1. Female members allowed to retain imperial status in case they marry commoners

Japanese lawmakers on Friday approved revisions to the law governing the world's oldest hereditary monarchy, retaining the country's male-only imperial succession rule.

Parliament, known as Diet, approved an amendment to the Imperial House Law “to address the issue of the shrinking royal family," Kyodo News reported.

This is the first major revision to the 1947 law, the daily said.

The changes allow the adoption of men aged 15 and older from former branch families descended from emperors through the male line and permit female members of the imperial family to retain their imperial status after marrying commoners.

Japan had removed 51 members of the 11 former branch families which descended from emperors, from the imperial family under the law.

The report said the conservative ruling coalition led by Prime Minister Sanae Takaichi – the first woman to lead Japan -- has “faced criticism from opposition lawmakers for insufficient parliamentary deliberations” as well as their “apparent push to preserve the tradition of male and paternal-line imperial succession.”

Why is Japan’s imperial family shrinking?

Japan's monarchy is said to date back over 2,600 years and the imperial family has steadily declined in size due to succession rules and demographic changes.

The 1947 Imperial House Law took effect when Japan was still under US occupation following World War II.

Under the Imperial House Law of 1947, only males in the paternal line may inherit the throne.

But following the historic revision to the law, now male descendants of those adopted into the imperial family could ascend the Chrysanthemum Throne.

Also, the female members, who wish to marry outside the imperial family, will no longer need to relinquish their imperial status.

However, their spouses or children, will be unable to join the imperial family and will remain commoners.

The revised law and implementation will be reviewed every 30 years, if needed.

Who can currently inherit the throne?

Today, the imperial family has fewer than 20 members, with only a handful of male heirs remaining.

Only males descended through the paternal imperial line remain eligible.

The current line of succession consists of: Crown Prince Akishino, the younger brother of Emperor Naruhito; Prince Hisahito, Akishino’s son; Prince Hitachi, the emperor’s elderly uncle; Prince Hisahito, born in 2006, is the youngest member of the succession line and currently the only heir of his generation. (AA)