By Chris Hogg
BBC News, Tokyo
Visitors to Tokyo who want to see where the Imperial Family live will be disappointed.
The closeted life of Japan's royalty has its price
The Japanese Imperial Palace, or Kokyo, is obscured almost completely by the gardens that surround it.
You can see part of it from a small part of the grounds open to the public but you cannot get close.
But this is not the only way the Imperial Family are isolated from their people.
All access to them is controlled rigidly by the Imperial Household Agency.
This is where the real power lies.
Professor Jeffrey Kingston from Temple University in Tokyo describes them as "a set of bureaucrats who keep the family on a tight rein and ensure that all of its members carry out their duties according to its dictates."
"Clearly the royals live in a gilded cage," he said.
"It is a very stressful life and although press scrutiny is far less intrusive than what is now common in Britain, for example, the Imperial Household Agency is very concerned about their public image."
So during photo calls at the palace no sound can be recorded for fear of some inappropriate "off the cuff" comment being captured.
They do, unlike the British Royal Family, give occasional press conferences. But these are carefully stage managed. The questions are approved in advance by palace officials. Deferential Japanese journalists follow the rules to the letter.
No wonder then that two of the women who have married into the family from outside - the Empress Michiko and the wife of the Crown Prince, Princess Masako - appear to have found its rules and restrictions so stressful.
The Imperial Household Agency said last week that Empress Michiko was again ill with symptoms linked to psychological stress, while Princess Masako has been rarely seen in public since late 2003 after suffering from a condition also brought on by stress.
When snippets of their real lives and tensions seep out, usually in the form of unsubstantiated rumours, there is huge public interest.
Michiko was the first commoner to marry an heir to the throne
The media, according to royal sources quoted by Japanese news agencies, is also at fault.
The news agency Kyodo reported recently that the empress's current health problems are being blamed on "gossipy" coverage of her family.
Midori Watanabe has been a royal-watcher in Japan for half a century.
She agrees that the pressure on the commoners who joined the Imperial Family comes from both inside and outside the palace.
"If I had a daughter I would never let her marry into the Imperial Family," she said. "It's too much".
She points out that aside from their official duties there are at least 20 rituals of the Shinto religion that the emperor and empress are obliged to take part in each year inside the palace behind closed doors.
For the empress each ritual requires a traditional cleansing, an elaborate costume with 12 layers, special hair style and make up.
"Obviously because the empress came from a good family she was taught to believe in the institution and wants to preserve the Imperial traditions and culture," she says.
"Perhaps Princess Masako wasn't so adaptive."
The Imperial Household Agency says the wife of the Crown Prince is suffering from an "adjustment disorder".
Some commentators believe she is suffering from serious depression.
Whatever the truth, she has been unable to carry out all but the most minor public duties for many months as the result of her mental health problems.
Midori Watanabe believes the fact that both the empress and the princess seem to be suffering conditions that do not have obvious physical symptoms makes it even harder for them.
Crown Prince Naruhito says his wife is slowly getting better
"When you see them on TV they look healthy," she said.
"That's hard because people probably look at them and think what's wrong with them? Perhaps it's more difficult to recover because their sickness isn't so apparent. Perhaps that's why they don't get well."
No longer divine
Professor Kingston said he sensed a great deal of sympathy for Princess Masako, among women especially.
"They understand and empathise with her difficulties in navigating the minefield of what is still a very patriarchal society," he said.
To many, the Japanese Imperial Household will seem like an anachronistic institution.
But it is an institution that has undergone some degree of modernisation in the past few decades.
Before World War II the emperor was regarded as a divine being. After Japan's defeat he was stripped of his divinity.
Since then the use of concubines to maintain the Imperial line has been abandoned. The current emperor and empress were the first to bring up their children themselves, rather than giving them up to nurses and officials.
More recently the emperor was allowed to repudiate the governor of Tokyo's efforts to force the singing of the national anthem. For years he had been prevented from uttering a single word - that might be interpreted as interference in a political issue.
But for those commoners who enter the "gilded cage", life is unlikely to get any easier.
The reality is that there is little public debate about whether or not the Imperial Household should be more open, or adopt the style and practices of other royal families. Those Japanese who really care about the Imperial Family and take an active interest in its affairs are mainly older and conservative, and probably more resistant to change.
Younger Japanese might take a more relaxed or liberal attitude. But for many of them it is an institution that has little relevance to their everyday life, and they take little interest in what goes on behind the walls of the palace.