Prince William begins significant tour of Japan and China

When his parents came to Tokyo nearly thirty years ago around 100,000 people lined the streets to see them.

Prince William on his own will not pull a crowd like that, although the presence of the Duchess of Cambridge might have gone some way towards matching the frenzy generated by Diana Princess of Wales back in the mid-eighties.

But Kate is seven months pregnant now and confining herself to public duties at home in Britain.

Less public excitement, perhaps, but this is a significant royal tour nevertheless.

Certainly for William, who sees it very much as part of the preparation for his eventual role as King.

He is anxious to understand the cultures of the two nations on his itinerary, Japan and China.

Both are economic powerhouses and important trading partners.

Amid all the pleasantries, there will be controversy. William's weekend visit to an area affected by the 2011 tsunami is viewed with scepticism by some of the people living there.

They believe his itinerary has been manipulated by the government to highlight it's re-building efforts and to promote it's continuing support of nuclear power, even after the crisis at the Fukushima plant.

In China, William will lobby for stricter controls on the sale of ivory and other products from endangered animals. It's the cause closest to his heart.

But his journey to Yunnan Province to see efforts to protect Asian elephants has already been undermined by reports that Chinese tourists there flock to shows in which elephants are forced to play football and perform circus tricks.

As he continues his royal duties, and confronts these issues, Prince William is preparing for change on the home front.

Kate is due to give birth to the couple's second child in around two months and William is about to start a new career.

He's passed all fourteen exams he needed for a civilian pilot's licence and will start work in an air ambulance early in the summer.