In a more relaxed image, also released yesterday, the Emperor and Empress are seen explaining a document to their kneeling seven-year-old grandson, Prince Hisahito – who will one day be emperor. Behind them their granddaughters Princess Mako, 22, and Princess Kako, 19 – both daughters of Prince Akishino and his wife – chat with their 12-year-old cousin Aiko, Princess Toshi.