Question: What year was the mother of Masako, Crown Princess of Japan born?

full_context: Document 1: 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 2: Princess Masako Takeda: Princess Masako Takeda (恒久王妃昌子内親王 , Tsunehisa Ōhi Masako naishinnō ) , born Masako, Princess Tsune (常宮昌子内親王 , Tsune-no-miya Masako Naishinnō , 30 September 1888 – 8 March 1940) , was the tenth child and sixth daughter of Emperor Meiji of Japan and one of his consorts, Sono Sachiko.
Document 3: Empress Michiko: Michiko (美智子 ) , born Michiko Shōda (正田美智子 , Shōda Michiko ) on 20 October 1934, is the Empress of Japan as the wife of Akihito, the current Emperor of Japan reigning from 7 January 1989. She succeeded her mother-in-law, Empress Nagako (Kōjun), consort of Emperor Hirohito (Shōwa).
Document 4: Kazuko Takatsukasa: Kazuko Takatsukasa (鷹司和子 , Takatsukasa Kazuko , 30 September 1929 – 26 May 1989) , formerly Kazuko, Princess Taka (孝宮和子内親王 , Taka-no-miya Kazuko Naishinnō ) , was the widow of Toshimichi Takatsukasa and third daughter of Emperor Shōwa and Empress Kōjun. She was an elder sister to the present Emperor of Japan, Emperor Akihito. She married Toshimichi Takatsukasa on 21 May 1950. As a result, she gave up her imperial title and left the Japanese Imperial Family, as required by law.
Document 5: 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 6: Setsuko, Princess Chichibu: Setsuko, Princess Chichibu (雍仁親王妃勢津子 , Yasuhito Shinnōhi Setsuko ) , born Setsuko Matsudaira (松平節子 , Matsudaira Setsuko , 9 September 1909 – 25 August 1995) , was a member of the Japanese Imperial Family. The Princess was the wife of Prince Chichibu, the second son of Emperor Taishō and Empress Teimei. She was, therefore, a sister-in-law of Emperor Shōwa and an aunt of the present emperor, Akihito.
Document 7: Masako Sen: Masako Sen (千容子 , Sen Masako , born 23 October 1951) , formerly Princess Masako of Mikasa (容子内親王 , Masako Naishinnō ) , is the fourth child and second daughter of Takahito, Prince Mikasa and Yuriko, Princess Mikasa. She married Soshitsu Sen on 14 October 1983. As a result, she gave up her imperial title and left the Japanese Imperial Family, as required by law.
Document 8: Kikuko, Princess Takamatsu: Kikuko, Princess Takamatsu (宣仁親王妃喜久子 , Nobuhito Shinnōhi Kikuko ) , born Kikuko Tokugawa (徳川喜久子 , Tokugawa Kikuko , 26 December 1911 – 18 December 2004) , known informally as Princess Kikuko, was a member of the Japanese Imperial Family. The Princess was the widow of Prince Takamatsu, the third son of Emperor Taishō and Empress Teimei. She was, therefore, a sister-in-law of Emperor Shōwa and an aunt of the present emperor, Akihito. She was mainly known for philanthropic activities, particular her patronage of cancer research organizations. At the time of her death, Princess Takamatsu was the oldest member of the Imperial Family.
Document 9: 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.
Document 10: 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 11: 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 12: 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 13: 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 14: 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 15: 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.
ground_truth: 1934