The lack of male heirs in Japan’s imperial family has sparked a debate over revising the Imperial House Law (1947). This law specifies that the imperial throne will be succeeded only by a male offspring in the male line belonging to the Imperial Lineage. The pros and cons of having a “female emperor” (josei tennō) or “matrilineal emperor” as a solution to the lack of eligible heirs has become the focus of this debate. The Imperial House Law is based on Articles 2-5 of the Constitution of Japan, which are part of Chapter I. The Emperor. These articles focus on matters related to imperial succession, and they prescribe other detailed matters regarding the Emperor and the Imperial Household. Since 2000, public-opinion polls have shown that support for a female emperor has remained high among members of the younger generations. According to an NHK opinion-poll in 2019, over 70% of the population has supported a matrilineal emperor since the beginning of the Reiwa era (2019- ). Some have pointed out that the increased support for a female emperor or matrilineal emperor did not necessarily arise because of the lack of heirs in the Imperial Family, but rather resulted from the rise in women’s rights and their rise in status within Japanese society. From a feminist perspective, unease about Japan’s patriarchal tradition of family succession by the male offspring in the male line has become more widespread. On the other hand, there is still persistent opposition from conservatives who support the point of view that imperial succession should follow the male (patrilineal) line form the Emperor Jinmu, the first emperor of Japan (this view is the so-called “unbroken imperial line”). There are also people who propose reinstating the old imperial house to preserve imperial succession. In addition, there were several female emperors in Japanese history, and among those who attach a great deal of importance to the “unbroken imperial line,” there are some who are against having an emperor from the female (matrilineal) line even if they agree with having a female emperor.
In 2004, when the debate over the problem of imperial succession had become more, the Koizumi cabinet established the Advisory Council on the Imperial Household Law, a private advisory panel. At that time, nearly 40 years had passed since the birth of the son of Emperor Akihito (the 125th emperor of Japan), Prince Akishino. Although the crown prince (who later became Emperor Naruhito, the 126th emperor of Japan) at that time had a daughter, Princess Aiko, he did not have any sons. In 2005, the Advisory Council published the Advisory Council on the Imperial House Law Report, which deemed it acceptable for Japan to have a female emperor or a matrilineal emperor. Preparations were made to revise the Imperial House Law based on that report. A positive tone in favor of Princess Aiko’s succession to the throne and the revisions to the Imperial House Law that would be necessary for that to happen had emerged. However, in 2006, Prince Akishino’s son, Prince Hisahito, was born. The debate over a female emperor or a matrilineal emperor were shelved. Still, the Imperial Household Law did not specify the “abdication of the emperor” (tennō no taii), but it was revised in 2017 to allow Emperor Akihito to abdicate. Even though the main articles of the Imperial House Law were not revised, supplementary provisions were added. Provisions regarding the emperor’s abdication were stipulated in the Special Measures Law on the Imperial House Law Concerning the Abdication of the Emperor and Other Matters (Tennō no taii tō ni kansuru kōshitsu tenpan tokureihō). Paragraph 4 of the supplementary provisions states that the Imperial House Law and the Special Measures Law “shall become unified” (ittai wo nasu mono dearu). This was the first time in the history of the Constitution that changes related to the imperial succession were added to the Imperial House Law.
Not only have the imperial heirs aged, but the entire imperial family has also aged. The number of members in the imperial family has also been decreasing. There is also growing concern over the increase of the emperor’s public duties and rituals and the difficulty of succession. One of the solutions to these problems that is being considered is the establishment of a female branch of the imperial family that is headed by female members of the imperial family. According to Article 12 of the Imperial Houselaw, if a “female of the Imperial Family marries a person other than the Emperor or the members of the Imperial Family, she shall lose the status of the Imperial Family member.” There has been a proposal that calls for revising this article to allow female members of the imperial family to retain their status as members of the imperial family after marriage.
Keywords: Imperial succession, Revision of Imperial Household Law, Female Emperors, Female-line succession, Creation of female-line royal families, Imperial family membership recovery