Chrysanthemum Throne in the context of "Daijō Tennō"

The current line of succession to the Chrysanthemum Throne is based on the Imperial Household Law. At present, only direct male-line males are allowed to ascend the throne.

Naruhito (born 23 February 1960) is Emperor of Japan. He acceded to the Chrysanthemum Throne following the abdication of his father, Akihito, on 1 May 2019, beginning the Reiwa era. He is the 126th monarch, according to the traditional order of succession.

Naruhito was born during the reign of his paternal grandfather, Emperor Hirohito. He was the first child of Crown Prince Akihito and Crown Princess Michiko (later Emperor and Empress). His father acceded to the throne in 1989 upon the death of Emperor Hirohito, making Naruhito the heir apparent. He was formally invested as Crown Prince of Japan in 1991. He attended Gakushūin schools in Tokyo and later studied history at Gakushuin University and English at Merton College, Oxford. In June 1993, he married the diplomat Masako Owada. They have one daughter: Aiko, Princess Toshi.

The 2019 Japanese imperial transition occurred on 30 April 2019 when the then 85-year-old Emperor Akihito of Japan abdicated from the Chrysanthemum Throne after reigning for 30 years, becoming the first Emperor of Japan to do so since Emperor Kōkaku in 1817. This marked the end of the Heisei era and the inception of the Reiwa era, and saw numerous festivities leading up to the accession of his eldest son and successor, Emperor Naruhito. The Enthronement Ceremony took place on 22 October 2019. Akihito's younger son, Prince Akishino, is his brother's heir presumptive. The ceremony cost 16.6 billion yen.

The Nanboku-chō period (南北朝時代, Nanboku-chō jidai), also known as the Northern and Southern Courts period, was a period in Japanese history between 1336 and 1392, during the formative years of the Muromachi (Ashikaga) shogunate. During this time, two opposing Imperial courts and their respective claimants as Emperor were engaged in conflict over their claims to the Chrysanthemum Throne, with the Southern Court ultimately renouncing their claim in favor of the Northern Court in 1392. This period became a source of contention for many Japanese historians and scholars over the following centuries. Initially, the North's victory in the dispute led official histories to paint them as the legitimate claimants. In reality, the Northern pretenders were simply puppet rulers under the direct control of the Kamakura and Ashikaga shogunates, while the Southern claimants maintained control of the Japanese Imperial Treasures, the sacred artifacts that confirmed an Emperor's legitimacy. To officially resolve this historical dilemma, in 1911 Emperor Meiji issued an edict that the Emperors of the Southern Court were the legitimate claimants during this period.

The destruction of the Kamakura shogunate of 1333 and the failure of the Kenmu Restoration in 1336 opened up a legitimacy crisis for the new shogunate. Institutional changes in the estate system (shōen) that formed the bedrock of the income of nobles and warriors altered the status of the various social groups. The establishment of the Ashikaga shogunate broadened the economic base of the warriors, while undercutting the noble proprietors. However, this trend had started already with the Kamakura bakufu.

Hirohito (裕仁; 29 April 1901 – 7 January 1989), posthumously honored as Emperor Shōwa (昭和天皇, Shōwa Tennō), was the 124th emperor of Japan according to the traditional order of succession, reigning from 1926 until his death in 1989. He remains the longest-reigning emperor in Japanese history and one of the longest-reigning monarchs in the world. As emperor during the Shōwa era, Hirohito presided over the rise of Japanese militarism, Japan's invasion of mainland Asia, the outbreak of the Second Sino-Japanese War, the Second World War, and the nation's postwar economic miracle.

Hirohito was born during the reign of his paternal grandfather, Emperor Meiji, as the first child of Crown Prince Yoshihito and Crown Princess Sadako (later Emperor Taishō and Empress Teimei). When Emperor Meiji died in 1912, Hirohito's father ascended the Chrysanthemum Throne, and Hirohito was proclaimed Crown Prince of Japan in 1916, making him the heir apparent. In 1921, he made an official visit to the United Kingdom and Western Europe, marking the first time a Japanese crown prince had traveled abroad. Due to his father's ill health, Hirohito became Sesshō of Japan (regent) that same year. In 1924, he married Princess Nagako Kuni, with whom he later had seven children: Shigeko, Sachiko, Kazuko, Atsuko, Akihito, Masahito and Takako. He became emperor upon his father's death in 1926.

A crown prince or hereditary prince is the heir apparent to the throne in a royal or imperial monarchy. The female form of the title, crown princess, is held by a woman who is heir apparent or is married to the heir apparent.

Crown prince as a descriptive term has been used throughout history for the prince who is first-in-line to a throne and is expected to succeed (i.e. the heir apparent), barring any unforeseen future event preventing this. In certain monarchies, a more specific substantive title may be accorded and become associated with the position of heir apparent (e.g. Prince of Wales in the United Kingdom, Prince of Asturias in the Kingdom of Spain and formerly the Dauphin in France). In these monarchies, the term crown prince may be used less often than the substantive title (or never).

The Heisei era (平成; Japanese: [heiːseiː] ) was the period of Japanese history corresponding to the reign of Emperor Akihito from 8 January 1989 until his abdication on 30 April 2019. The Heisei era started on 8 January 1989, the day after the death of the Emperor Hirohito, when his son, Akihito, acceded to the throne as the 125th emperor of Japan. In accordance with Japanese customs, Hirohito was posthumously renamed "Emperor Shōwa" on 31 January 1989.

Thus, 1989 corresponds to Shōwa 64 up until 7 January and Heisei 1 (平成元年, Heisei gannen; gannen means "first year") from 8 January. The Heisei era ended on 30 April 2019 (Heisei 31), with the abdication of Akihito from the Chrysanthemum Throne. It was succeeded by the Reiwa era as then-crown prince Naruhito ascended the throne on 1 May midnight local time.