The Princess has a lot of solo engagements....Does she attend many events on her own?
In photographs, she mostly seems in company with her husband or other family members.
People age differently. Some get Alzheimers at 60, others are still as lively as their grandchildren (or even more...) when they are 88. The emperor should have the possibility to abdicate if he wants to. (Although I doubt that he wants. Already some years ago, the crown prince said that he was indeed worried because of his father´s huge workload but that, according to his perception, the emperor cherished his imperial duties and would not take kindly to being "freed" of them.)There's no need for a retirement age. The emperor's father was doing fine at 77. What is needed is a mechanism for abdication. Before the Meiji period, when State Shinto made the emperor into a god, it was very common for emperors to abdicate after only a few years.
HIH the Princess Kiko during the luncheon with the Costarican president on December 8th, 2011.
**Pic** - Fuji TV screencapture
Like her kimono's colour and pattern.