Aiko, Princess Toshi

In the summer of 2018, she made her first solo trip abroad to attend a summer program at Eton College. After her return, she confidently answered questions from the press and took on the role of emcee for her school's dance team performance. Reports from an unnamed palace source close to the family reported that Aiko provides her mother Masako with emotional support in her new role as Empress. In February 2020 she was accepted at Gakushuin University where she is to major in Japanese language and literature.

She visited a special exhibition on the 150th anniversary of Japan–Italy diplomatic relations on 5 April 2016 at the Tokyo museum. Since turning 16, she has accompanied her parents at public appearances. Princess Aiko was ineligible to attend any of her father’s ascension ceremonies in person as she is still a minor. According to Imperial House Law, Article 22, she will reach the age of maturity on her twentieth birthday in 2021.

In November 2011, Aiko was hospitalized with pneumonia. In 2014, she enrolled at the Gakushuin Girl's Junior High-school.

In early March 2010, Aiko began to stay home from school due to not getting along with other children and being bullied by her elementary school classmates. Aiko returned to school on a limited basis on 2 May 2010. After returning to school, a senior palace official said that she would attend a limited number of classes accompanied by her mother, upon advice from a doctor at the Crown Prince's household.

Princess Aiko began her education at Gakushuin Kindergarten on 3 April 2006. She left kindergarten on 15 March 2008.

Proposals to replace agnatic primogeniture were shelved temporarily after it was announced in February 2006 that the-then Crown Prince's younger brother, Fumihito, Prince Akishino, and his wife, Kiko, Princess Akishino, were expecting their third child. On 6 September 2006, Princess Kiko gave birth to a son, Hisahito, who was third in line to the Chrysanthemum Throne at the time of the birth under the current law, after his uncle, the then-Crown Prince, and his father, Prince Akishino. The prince's birth provided the first male heir to be born in the imperial family in 41 years. On 3 January 2007, Prime Minister Shinzō Abe announced that he would drop the proposal to alter the Imperial Household Law. Therefore, at this time, it seems unlikely that the succession laws will be changed to allow Princess Aiko to ascend the throne.

A government-appointed panel of experts submitted a report on 25 October 2005, recommending that the Imperial succession law be amended to permit absolute primogeniture. On 20 January 2006, Prime Minister Junichiro Koizumi used part of his annual keynote speech to address the controversy when he pledged to submit a bill to the Diet letting women ascend to the throne in order that the Imperial throne be continued into the future in a stable manner. Koizumi did not announce a timing for the legislation to be introduced nor did he provide details about the content, but he did note that it would be in line with the conclusions of the 2005 government panel.

Aiko, Princess Toshi (敬宮愛子内親王 , Toshi-no-miya Aiko Naishinnō, born 1 December 2001) is the only child of Emperor Naruhito and Empress Masako of Japan.

Princess Aiko was born on 1 December 2001 at 2:43 PM in the Imperial Household Agency Hospital in Tokyo Imperial Palace, the first child and only daughter of the then-Crown Prince and Crown Princess, Naruhito and Masako.

The Imperial Household Law of 1947 abolished the Japanese nobility; under provisions of this law, the imperial family was streamlined to the descendants of Emperor Taishō. The laws of succession in Japan prevent inheritance by or through the female line.

The birth of Princess Aiko sparked debate in Japan about whether the Imperial Household Law of 1947 should be changed from the current system of agnatic primogeniture to absolute primogeniture, which would allow a woman, as firstborn, to inherit the Chrysanthemum Throne ahead of a younger brother or male cousin. Although Imperial chronologies include eight empresses regnant in the course of Japanese history, their successors were always selected from amongst the members of the paternal Imperial bloodline, which is why some conservative scholars argue that the women's reigns were temporary and that male-only succession tradition must be maintained in the 21st century. Though Empress Genmei was followed on the throne by her daughter, Empress Genshō, Genshō herself was succeeded by her brother's son, thus keeping the throne in the same agnatic line; both Genshō and Genmei, as well as all other empresses regnant and emperors, belonged to the same patriline.