Question: Prince Hisahito of Akishino's father was born in what year?

full_context: Document 1: Prince Hisahito of Akishino: Prince Hisahito of Akishino (悠仁親王 , Hisahito Shinnō , born 6 September 2006) is the youngest child and only son of Fumihito, Prince Akishino and Kiko, Princess Akishino. He is the only grandson of Emperor Akihito and Empress Michiko. Hisahito is third in line to become Emperor of Japan, after his uncle Naruhito and his father.
Document 2: Takako Shimazu: Takako Shimazu (島津貴子 , Shimazu Takako , born 2 March 1939) , born Takako, Princess Suga (清宮貴子内親王 , Suga-no-miya Takako Naishinnō ) , is a member of the Imperial House of Japan. She is the fifth and youngest daughter of Emperor Shōwa and Empress Kōjun, and the youngest sister of the current Emperor of Japan, Akihito. She married Hisanaga Shimazu on 3 March 1960. As a result, she gave up her imperial title and left the Japanese Imperial Family, as required by law.
Document 3: Princess Kako of Akishino: Princess Kako of Akishino (佳子内親王 , Kako Naishinnō , born 29 December 1994) is the second daughter of Fumihito, Prince Akishino and Kiko, Princess Akishino, and a member of the Japanese Imperial Family. She is the second-eldest grandchild of Emperor Akihito and Empress Michiko.
Document 4: Aiko, Princess Toshi: Aiko, Princess Toshi (敬宮愛子内親王 , Toshi-no-miya Aiko Naishinnō , born 1 December 2001) is the only child of Crown Prince Naruhito and Crown Princess Masako of Japan.
Document 5: Kiko, Princess Akishino: Kiko, Princess Akishino (文仁親王妃紀子 , Fumihito Shinnōhi Kiko ) , born 11 September 1966 as Kiko Kawashima (川嶋紀子 , "Kawashima Kiko" ) , is the wife of Fumihito, Prince Akishino, the second son of Emperor Akihito and Empress Michiko of Japan. She is also known as Princess Kiko.
Document 6: Hanako, Princess Hitachi: Hanako, Princess Hitachi (正仁親王妃華子 , Masahito Shinnōhi Hanako ) , born Hanako Tsugaru (津軽華子 , Tsugaru Hanako ) on 19 July 1940, is a member of the Japanese Imperial Family as the wife of Masahito, Prince Hitachi, who is the younger son of Emperor Shōwa and the only brother of the current emperor, Akihito.
Document 7: Prince George of Cambridge: Prince George of Cambridge (George Alexander Louis; born 22 July 2013) is the elder child and only son of Prince William, Duke of Cambridge, and Catherine, Duchess of Cambridge. He is third in line of succession to the British throne, after his paternal grandfather, and father.
Document 8: Fumihito, Prince Akishino: Fumihito, Prince Akishino (秋篠宮文仁親王 , Akishino-no-miya Fumihito Shinnō , born 30 November 1965) is a member of the Japanese imperial family. He is the younger son of Emperor Akihito and Empress Michiko and currently second in line to the Chrysanthemum Throne.
Document 9: Dipangkorn Rasmijoti: Prince Dipangkorn Rasmijoti (born 29 April 2005; Thai: ทีปังกรรัศมีโชติ ; rtgs: "Thipangkon Ratsamichot" ;  ] ) is a member of the country's Chakri dynasty and heir presumptive to the throne of Thailand. He is the fifth son of King Vajiralongkorn. His mother is Srirasmi Suwadee, the king's third legal wife. His father also has a daughter by his first wife and five children (four sons and a daughter) by his second wife; all the children of the second wife were born before the then-crown prince married their mother but after the Crown Prince married her the 5 children were legitimised by marriage. After the Crown Prince divorced his second wife in 1996, he disowned her sons. Thus, Dipangkorn is the only recognised son of the king.
Document 10: Masako, Crown Princess of Japan: Masako, Crown Princess of Japan (皇太子徳仁親王妃雅子 , Kōtaishi Naruhito Shinnōhi Masako ) , born Masako Owada (小和田雅子 , "Owada Masako" ) on 9 December 1963, is the wife of Naruhito, Crown Prince of Japan, who is the eldest son of Emperor Akihito and Empress Michiko and the heir apparent to the Chrysanthemum Throne. She is a member of the Imperial House of Japan through marriage. Should the Crown Prince ascend the throne as expected upon his father's abdication, Masako will become empress consort.
Document 11: Princess Mako of Akishino: Princess Mako of Akishino (眞子内親王 , Mako Naishinnō , born 23 October 1991) is the first child and oldest daughter of Fumihito, Prince Akishino and Kiko, Princess Akishino, and a member of the Japanese Imperial Family. She is the eldest grandchild of Emperor Akihito and Empress Michiko.
Document 12: Prince Kuni Asaakira: Prince Kuni Asaakira (久邇宮 朝融王 , Kuni-no-miya Asaakira-ō , 2 February 1901 – 7 December 1959) , was third head of the Kuni-no-miya, a collateral branch of the Japanese imperial family and vice admiral in the Japanese Imperial Navy during World War II. He was the elder brother of Empress Kojun (Nagako), the consort of Emperor Shōwa (Hirohito), and thus a maternal uncle to the current Emperor Akihito.
Document 13: Prince Harry: Prince Henry of Wales {'1': ", '2': ", '3': ", '4': "} (Henry Charles Albert David; born 15 September 1984), familiarly known as Prince Harry, is the younger son of Charles, Prince of Wales, and Diana, Princess of Wales. At the time of his birth, he was third in line of succession to the British throne, after his father and elder brother, but is currently fifth in line after his father, his elder brother, and his nephew and niece, George and Charlotte.
Document 14: Masahito, Prince Hitachi: Masahito, Prince Hitachi (常陸宮正仁親王 , Hitachi-no-miya Masahito Shinnō , born 28 November 1935) is a member of the Imperial House of Japan and the younger brother of current Emperor Akihito. He is the second son and sixth born child of Emperor Shōwa and Empress Kōjun and is fourth in line to the Chrysanthemum Throne. Prince Hitachi is mainly known for philanthropic activities and his research on the causes of cancer.
Document 15: Prince Nobuhiko Higashikuni: Prince Nobuhiko Higashikuni (b. 東久邇 信彦; 10 March 1945）is a Japanese aristocrat. The eldest grandson of Emperor Hirohito, he is the eldest son of Shigeko, Princess Teru (the eldest daughter of Emperor Hirohito, and eldest sister of present Emperor Akihito) and Prince Morihiro Higashikuni, a grandson of Emperor Meiji. He is nephew of reigning Emperor Akihito.
ground_truth: 1965