Arrived Christmas Eve and spent a few days in Tokyo. Bullet train to Kyoto for a few days, then on to Hiroshima and Miyajima for New Year, then back to Tokyo for three days.
Paid for a bespoke company to set it up: top of the line hotels, tickets pre-booked for the bullet train and attractions etc. Cost a fortune, but a priceless experience.
Need to go back, though: would do Tokyo again and Osaka.