Question: which Empress of Japan has , Naruhito, Crown Prince of Japan as her  elder son 
Context: Empress Dowager Dong (died 189), personal name unknown, formally known as Empress Xiaoren, was an empress dowager of the Eastern Han dynasty.  She was never empress throughout her life because she was the wife of a marquis; she only became empress dowager because her son, Liu Hong (Emperor Ling), became the emperor by chance.  During her son's reign, she developed a rivalry with her daughter-in-law, Empress He, because she wanted Emperor Ling's younger son, Liu Xie, to be crown prince while Empress He wanted her own son, Liu Bian to succeed his father.  Emperor Ling died in 189 before he managed to designate either of his two sons as crown prince.  Liu Bian eventually took the throne as Emperor Shao; Empress Dowager Dong, as the emperor's grandmother, became grand empress dowager, while her daughter-in-law became empress dowager.  Empress Dowager He eventually conspired with her brother, General-in-Chief He Jin, to unseat her mother-in-law from power.  Grand Empress Dowager Dong died of illness shortly after her downfall; the common people held Empress Dowager He and her family responsible for the grand empress dowager's death. Zhangsun Wuji (died 659), courtesy name Fuji, formally the Duke of Zhao (趙公 ), was a Chinese official who served as a chancellor in the early Tang dynasty.  He was Empress Zhangsun's brother, which made him a brother-in-law of Emperor Taizong (Li Shimin) and a maternal uncle of Emperor Gaozong (Li Zhi).  He was an important advisor to Li Shimin when the latter was still the Prince of Qin during the reign of his father, Emperor Gaozu.  He helped Li Shimin overcome his brothers Li Jiancheng (the Crown Prince) and Li Yuanji (the Prince of Qi) in a succession struggle at the Xuanwu Gate Incident, eventually enabling Li Shimin to become the heir apparent and later the emperor.  He was also instrumental in Emperor Taizong's selection of Li Zhi as the Crown Prince, and was exceedingly powerful after Li Zhi took the throne as Emperor Gaozong.  However, he gradually fell out of his nephew's favour by failing to support Emperor Gaozong's decision to depose his first wife, Empress Wang, and replacing her with Empress Wu.  In 659, Zhangsun Wuji was falsely accused of treason by Empress Wu's political ally, Xu Jingzong, and eventually ordered to be sent into exile by Emperor Gaozong.  Xu Jingzong subsequently sent the official Yuan Gongyu (袁公瑜) to force Zhangsun Wuji to commit suicide on his way to exile. Li Chongjun (李重俊) (died 7 August 707), formally Crown Prince Jiemin (節愍太子), was a crown prince of the Chinese dynasty Tang Dynasty, during the second reign of his father Emperor Zhongzong.  He was made crown prince because the only son of his father's wife Empress Wei, Li Chongrun, had been killed before his father's return to the throne, but on account of his mother's low birth, he was often humiliated by Empress Wei's daughter Li Guo'er the Princess Anle and her husband Wu Chongxun (武崇訓).  In 707, in anger, he started a coup and killed Wu Chongxun and his father Wu Sansi the Prince of Dejing, but his subsequent attempt to arrest Empress Wei, Li Guo'er, and Consort Shangguan Wan'er was thwarted, and he was killed in flight. Muqrin bin Abdulaziz Al Saud (Arabic: مقرن بن عبدالعزيز آل سعود‎ ‎ ; born 15 September 1945) is a member of House of Saud who served as Crown Prince of Saudi Arabia from January to April 2015.  He was Director General of Al Mukhabarat Al A'amah (Saudi Intelligence Agency) from 2005 to 2012.  In July 2012, Muqrin was appointed King Abdullah's Advisor and Special Envoy with the rank of minister.  On 1 February 2013, King Abdullah named him as Second Deputy Prime Minister, being the fifth Saudi royal to hold this position.  This post was previously held by King Fahd, King Abdullah, Crown Prince Sultan, and Crown Prince Nayef.  On 27 March 2014, he was named Deputy Crown Prince making him second in the line of succession behind his brother Salman bin Abdulaziz Al Saud.  On 23 January 2015, upon King Abdullah's death and the accession of King Salman, Muqrin became Crown Prince and First Deputy Prime Minister.  On 29 April 2015, King Salman replaced Prince Muqrin with Prince Muhammad bin Nayef as Crown Prince. Li Zhong (李忠) (643 – January 6, 665), courtesy name Zhengben (正本), formally Prince of Yan (燕王), was a crown prince of the Chinese dynasty Tang Dynasty.  He was the oldest son of Emperor Gaozong (Li Zhi) and was created crown prince in 652 even though he was not the son of his then-wife Empress Wang.  After Empress Wang was displaced by Empress Wu (later known as Wu Zetian) in 655, however, Li Zhong was caught in Empress Wu's crosshairs and was forced to yield the crown prince position to his younger brother Li Hong, born of Empress Wu, in 656.  He was later further reduced to commoner rank and put under house arrest, and when the chancellor Shangguan Yi failed in his attempt to persuade Emperor Gaozong to depose Empress Wu in 664 and was executed, Empress Wu took the opportunity to accuse Li Zhong of being complicit in Shangguan's plans.  Around the new year 665, Emperor Gaozong ordered Li Zhong to commit suicide.  He was posthumously honored an imperial prince, but not a crown prince, during the second reign of his brother Emperor Zhongzong. 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. Wilhelm, German Crown Prince (German: "Kronprinz Wilhelm von Preußen" ; 6 May 1882 – 20 July 1951) , full name Friedrich Wilhelm Victor August Ernst, was the eldest child of the future German Emperor Wilhelm II and his wife Empress Augusta Victoria, and the last Crown Prince of the German Empire and the Kingdom of Prussia.  After the death of his grandfather Emperor Frederick III, Wilhelm became crown prince at the age of six, retaining that title for more than 30 years until the fall of the empire on 5 November 1918.  During World War I, he commanded the 5th Army from 1914 to 1916 and was commander of Army Group German Crown Prince for the remainder of the war.  Crown Prince Wilhelm became Head of the House of Hohenzollern on 4 June 1941 following the death of his father and held the position until his own death on 20 July 1951. Li Xian () (653–684), courtesy name Mingyun (), formally Crown Prince Zhanghuai (), named Li De () from 672 to 674, was a crown prince of the Chinese Tang Dynasty.  He was the sixth son of Emperor Gaozong, and the second son of his second wife Empress Wu (later known as Wu Zetian).  He was known for writing commentaries for the "Book of Later Han", the official history of the Eastern Han Dynasty.  He became crown prince in 675 after his older brother Li Hong's death (which traditional historians believed to be a poisoning by Empress Wu), but soon fell out of favor with Empress Wu herself.  In 680, Empress Wu had her associates accuse Li Xian of treason, and he was demoted to commoner rank and exiled.  In 684, after Emperor Gaozong's death, Empress Wu, then empress dowager, had her associate Qiu Shenji (丘神勣) visit Li Xian to force him to commit suicide. 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). Naruhito, Crown Prince of Japan (皇太子徳仁親王 , Kōtaishi Naruhito Shinnō , born 23 February 1960) is the elder son of Emperor Akihito and Empress Michiko, which makes him the heir apparent to the Chrysanthemum Throne.
Answer: Empress Michiko