Question: In which year was Emperor Akihito's eldest son's only daughter born?
Sentence (from "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.
Relevant evidence: Yes