Britain's Prince William, Duke of Cambridge, signs a guest book next to an newspaper clip reporting his later mother Diana, at Hodogaya Commonwealth War Graves Cemetery in Yokohama, south of Tokyo February 27, 2015, in this photo released by Kyodo. Diana visited the cemetery in February 7, 1995. The cemetery is the only Commonwealth War Graves Commission facility in Japan where about 1,800 British, Australian, New Zealand and Indian servicemen and women are buried. Prince William is in Japan for a four-day visit. [Photo/Agencies]