Japan's Emperor Akihito and Empress Michiko have revealed their secret wishes to have more time to take long walks and to be invisible. In a rare candid moment, the royal couple spoke openly with reporters at a news conference on Monday, ahead of their trip to the Baltic States, Britain and Sweden.

The emperor, 70, who is an eager scientist, said: "There is nothing that comes to mind that I would like to hide my status to do."

But he confessed he often wishes he had more time to do research and "take long walks."

His wife, the empress, admitted she often fantasized about becoming invisible. The 72-year-old described an incident when she wanted to attend an art exhibition, but had been unable to go due to concerns over crowd problems.

Michiko joked that donning an invisibility-cloak "might cause problems for the police."

The royal couple are scheduled to depart from Japan to embark on their 10-day tour on May 21. Stockholm will be their first stop, where they will meet with Sweden's King Carl XVI Gustaf and Queen Silvia.

The Nordic nation will be celebrating the 300th anniversary of Carl Linnaeus, Sweden's most famous scientist who pioneered the international standard for the classification of living organisms.

The emperor and empress will then visit Estonia, Latvia and Lithuania and meet with Eastern European leaders.

The trip will end in London, where the couple are set to meet Britain's Queen Elizabeth. Michiko reassured the conference that she was well enough to join her husband on the tour, despite recent ill health.

The princess had been suffering from nosebleeds, mouth ulcers and bleeding intestine walls - alignments which the palace reported were brought about by stress.

The empress said: "I have never had such an illness before, but I have gotten enough rest and I am recovered."