For the Imperial household, i.e. the court which serves the imperial family, see Imperial Household Agency
The Imperial House of Japan (also referred to as the Imperial Family or kōshitsu, 皇室) comprises those members of the extended family of the reigning Emperor of Japan who undertake official and public duties. Under the present Constitution of Japan, the emperor is the symbol of the state and unity of the people. Although he is not technically head of state, he is frequently treated as one. Other members of the imperial family perform ceremonial and social duties but have no role in the affairs of government.
The Japanese monarchy is the oldest continuous hereditary monarchy in the world still in existence. The imperial house recognizes 125 legitimate monarchs since the accession of Emperor Jimmu (traditionally dated to February 11, 660 BC), including the reigning emperor, Akihito. Most historians regard the first 14 emperors (Emperor Jimmu to Emperor Chuai) as mythical figures.

Current members of the imperial family
The following pedigree shows the current members of the imperial family.

Pedigree
Under the terms of the 1947 Imperial House Law, naishinnō (imperial princesses) and nyoō (princesses) lose their titles and membership in the imperial family upon marriage, unless they marry the Emperor or another member of the imperial family. Three of the five daughters of Emperor Shōwa, the two daughters of Prince Mikasa, and most recently, the only daughter of the Emperor Akihito left the imperial family upon marriage, taking the surnames of their husbands. (The eldest daughter of Emperor Shōwa married the eldest son of Prince Higashikuni Naruhiko in 1943. The Higashikuni family lost its imperial status along with the other collateral branches of the imperial family in October 1947). The living former imperial princesses (whose personal names are in parentheses) are:
In addition to these former princesses, there are also descendants of the eleven cadet branches of the dynasty (Asaka, Fushimi, Higashi-Fushimi, Higashi-kuni, Kan'in, Kaya, Kitashirakawa, Kuni, Nashimoto, Takeda, and Yamashina) that left the imperial family in October 1947. The Shōwa emperor's eldest daughter, Mrs. Higashikuni Morihito (Shigeko), and his third daughter, Mrs. Takatukasa Toshimichi (Kazuko), died in 1961 and 1989, respectively.

Mrs. Ikeda Takamasa (Atsuko), born 7 March 1931, fourth daughter of Emperor Shōwa and surviving elder sister of Emperor Akihito.
Mrs. Shimazu Hisanaga (Takako), born 2 March 1939, fifth daughter and youngest child of Emperor Shōwa and younger sister of Emperor Akihito.
Mrs. Konoe Tadateru (Yasuko), born 26 April 1944, eldest daughter and eldest child of Prince and Princess Mikasa.
Mrs. Sen Soshitsu (Masako), born 23 October 1951, second daughter and fourth child of Prince and Princess Mikasa.
Mrs. Kuroda Yoshiki (Sayako), born 18 April 1969, third child and only daughter of Emperor Akihito and Empress Michiko. Living former members of the imperial family
See also Emperor of Japan: Succession.
Historically, the succession to Japan's Chrysanthemum Throne has generally passed in male line of the imperial lineage. The imperial clan previously included specially designated collateral lines or shinnōke (princely houses), too. The surviving shinnōke and several other branches of the extended imperial clan (the ōke) were reduced to commoner status in 1947.
Before the Meiji Restoration, Japan had eight female tennō or reigning empresses, all of them daughters of male line of the imperial clan. None ascended purely as a wife or as a widow of emperor. None of these empresses married or gave birth after ascending the throne.
Article 2 of the Constitution of Japan provides that "The Imperial Throne shall be dynastic and succeeded to in accordance with the Imperial House Law passed by the Diet." The Imperial Household Law of 1947 enacted by the 92nd and last session of the Imperial Diet, retained the exclusion on female dynasts found in the 1889 law. The government of Prime Minister Yoshida Shigeru hastily cobbled together the legislation to bring the Imperial House in compliance with the American-written Constitution of Japan that went into effect in May 1947. In an effort to control the size of the imperial family, the law stipulates that only legitimate male descendants in the male line can be dynasts; that naishinnō (imperial princesses) and nyoō (princesses) lose their status as imperial family-members if they marry outside the imperial family; that shinnō (imperial princes), other than the crown prince, ō (princes), unmarried imperial princesses and princesses, and the widows of imperial princes and princesses may, upon their own request or in the event of special circumstances, renounce their membership in the imperial family with approval of the Imperial House Council; and that the Emperor and other members of the imperial family may not adopt children.
Before September 2006, there was a potential succession crisis since no male child had been born into the imperial family since Prince Akishino in 1965. Following the birth of Princess Aiko, there was some public debate about amending the Imperial House Law to allow female descendants of an emperor and their descendants to succeed to the throne. In January 2005, Prime Minister Koizumi Junichiro appointed a special panel of judges, university professors, and civil servants to study changes to the Imperial House Law and to make recommendations to the government. On October 25, 2005, the commission recommended amending the law to allow females in the male line of imperial descent to succeed to the throne. There is broad public support for such a change. See Japanese Imperial succession controversy.

Succession
Bahrain Belgium Bhutan Brunei Cambodia Denmark Japan Jordan Kuwait Lesotho Liechtenstein Luxembourg Malaysia Monaco Morocco Nepal Netherlands Norway Oman Qatar Saudi Arabia Spain Swaziland Sweden Thailand Tonga United Kingdom Crown Prince Naruhito has a daughter (Aiko) and Prince Akishino currently has two daughters (Mako and Kako) and a son (Hisahito). The emperor's brother, Prince Hitachi, is childless. Of the three sons of Prince Mikasa: Prince Tomohito of Mikasa has two daughters (Akiko and Yōko), Prince Katsura is childless, and the late Prince Takamado had three daughters (Tsuguko, Noriko, and Ayako).

His Imperial Highness Crown Prince Naruhito, born 1960, the current Emperor's first son
His Imperial Highness Prince Akishino (Fumihito), born 1965, the current Emperor's second son
His Imperial Highness Prince Hisahito of Akishino, born September 6, 2006 [1], Prince Akishino's son
His Imperial Highness Prince Hitachi (Masahito), born 1935, the current Emperor's brother
His Imperial Highness Prince Mikasa (Takahito), born 1915, the current Emperor's uncle (the brother of Hirohito)
His Imperial Highness Prince Tomohito of Mikasa, born 1946, Prince Mikasa's first son (the current Emperor's eldest male cousin)
His Imperial Highness Prince Katsura (Yoshihito), born 1948, Prince Mikasa's second son (the current Emperor's second eldest male cousin) Current order of succession
Aside from amending the Imperial House Law to allow women to succeed to the throne, which a commission suggested, there were several other scenarios that could have produced a male heir.
Allowing members of the imperial family to adopt children or reinstating one or more of the abolished cadet lines to imperial status were both possibilities, and there were a limited number of other viable solutions.
In theory, one of other male members of the imperial family could have produced a son, but this was considered very unlikely for various reasons.
Theoretically, the imperial family may have come to end after the last male heir died, since an heir must descend from the male line.
The pregnancy of Princess Kiko was announced that on February 6, 2006. She gave birth on September 6, 2006. The baby, Prince Hisahito of Akishino[2] (using the Chinese characters for "virtuous, calm, and everlasting") will be third in line to the throne, behind his father and his uncle.[3]
This birth temporarily abates the looming succession crisis, although the problem could resurface if anything untoward happens to the child before he can sire a male offspring. Prince Hisahito is the only male and heir of his generation, and he could eventually become the only member of the Japanese Royal Family.
It has been suggested that the succession laws could be changed into an Equal Primogeniture system, allowing the line of succession to grow significantly. The order of succession would then become:

Crown Prince Naruhito could have attempted to produce a male heir.
Prince Akishino could have continued attempts to produce a male heir (which he did).
Prince Katsura could have married and produced a male heir.
The wives of Prince Hitachi and Prince Tomohito of Mikasa were long past childbearing age.
If concubines had been the solution, then it would have applied to the Crown Prince first.
Prince Katsura has been paralyzed from the waist down and uses a wheelchair since suffering a series of strokes in 1988.
Crown Prince Naruhito, the Emperor's eldest son (b 1960)
Princess Aiko, the Crown Prince's daughter (b. 2001)
Prince Akishino, the Emperor's younger son (b. 1965)
Princess Mako of Akishino, Prince Akishino's eldest child (b. 1991)
Princess Kako of Akishino, Prince Akishino's second child (b. 1994)
Prince Hisahito of Akishino, Prince Akishino's third child (b. 2006)
Prince Hitachi, the Emperor's younger brother (b. 1935)
Prince Mikasa, the Emperor's uncle (b. 1915)
Prince Tomohito of Mikasa, Prince Mikasa's eldest son (b. 1946)
Princess Akiko, Prince Tomohito's eldest daughter (b. 1981)
Princess Yōko, Prince Tomohito's younger daughter, (b. 1983)
Prince Katsura, Prince Mikasa's second son (b. 1948)
Princess Tsuguko, eldest daughter of the late Prince Takamado, Prince Mikasa's third son (b. 1986)
Princess Noriko, Prince Takamado's second daughter (b. 1988)
Princess Ayako, Prince Takamado's third daughter (b. 1990) Possible succession scenarios
Ō (王) is a title (commonly translated Prince) given to male members of the Japanese Imperial Family who do not have the higher title of shinnō. The female equivalent is nyoō (女王). Ō can also be translated as "king". The origin of this double meaning is a copying of the Chinese pattern. Unlike in China, however, ō was only used for imperial family members. Interestingly, "queen" is joō, using the same characters as nyoō.
Historically, any male member of the Imperial Family was titled ō by default, with shinnō (親王; literally relative-prince) and its female equivalent naishinnō (内親王; literally relative-princess) being special titles granted by the Emperor. After the Meiji Restoration, the difference between ō and shinnō were altered. A shinnō or naishinnō was a legitimate Imperial Family member descended from an Emperor down to the great grandchild. The term "legitimate Imperial Family" excludes anyone not connected by a direct male line descent, as well as the descendants of anyone who renounced their membership in the Imperial Family, or were expelled from the Imperial Family. Shinnō also included the heads of any of the shinnōke. A provision of law which never had an opportunity to be applied also stipulated that if the head of a shinnōke succeeded to the Chrysanthemum Throne, then his brothers would acquire the title of shinnō, as well as their descendants (down to the grandchildren?). The Emperor could also specially grant the title of shinnō to any ō.
In 1947, the law was changed so that shinnō only extended to the male-line grandchildren of an Emperor. The Imperial Family was also drastically pruned, disestablishing the ōke and shinnōke. The consort of an ō or shinnō has the suffix -hi (妃) to ō or shinnō.

Related terms

Emperor
Empress
Crown prince
Royal family
Japanese imperial succession controversy
Monarchy
Monarch
Prince
Princess
Order of succession
Three Palace Sanctuaries