Emperor Akihito announced his desire to abdicate a year ago, now, the government of Japan has approved a special bill which will allow Emperor to do it.
In a rare televised address to the nation last August, the emperor, who has had health issues such as prostate cancer, indicated that at 83, he was not sure he would be able to continue to perform his duties for much longer.
But there is no provision under the existing law for him to abdicate and be succeeded by Crown Prince Naruhito.
No abdication is expected until at least the end of 2018, according to reports.
The leading opposition Democratic Party has argued the law should be permanently changed to ensure stable future successions but has reportedly agreed to the current one-off bill after talks with the ruling bloc.
The Emperor's Birthday holiday on December 23 will be changed to February 23, the birthday of Crown Prince Naruhito, said the bill.
While no definite plan for an abdication has been confirmed, media have said it will likely take place in late 2018, which would mark almost 30 full years on the throne for the emperor. It will permit the increasingly frail Akihito to abdicate in favour of his eldest son, Crown Prince Naruhito.
The legislation for Akihito's case was needed because the Imperial House Law does not provide for abdication.
Naruhito's younger brother, Prince Akishino, is next in line.
Mako's marriage to Kei Komuro, a former university classmate, will force her to relinquish her royal status, leaving one less members of the imperial family to carry out official duties.
In 2005, with hopes for a male heir fading, then-prime minister Junichiro Koizumi prepared to challenge a 1947 law limiting succession to male descendants of an emperor.
After the envisioned abdication, the emperor and empress are expected to move to Togu Palace in the Akasaka Estate in Tokyo's Minato Ward, where the crown prince and his family now live, and the new emperor's family will move to the Imperial Palace in Tokyo's Chiyoda Ward.
"It is urgent that the system should be reformed so that female members can remain in the imperial family", Isao Tokoro, professor emeritus of legal history at Kyoto Sangyo University, told the Times.
Now, Japan's government needs to approve the one-off bill which, if passed, will allow Emperor to abdicate.