Last year at Golden Week, Japan's unofficial spring vacation, Crown Prince Akihito and family members had to go to Yokohama. So they took a commuter train, with palace officials explaining the prince was concerned that a motorcade would make the holiday traffic even worse. An entire railcar was cleared and the royal travelers sat in solitude on a long velveteen seat, their backs to the windows, for the 50-minute ride from Tokyo.

It was hardly an ordinary encounter with Japan's legendarily crowded transit system, but by the standards of the prince's father, Hirohito, it was outright adventure. It was new evidence that the Chrysanthemum Curtain that shields the Japanese imperial family will lift an inch or two when the prince finally becomes emperor.

The British worry over heirs slipping into dissipation during the long wait for the throne. Akihito is now in his 34th year of standing at the ready but shows no signs of impatience or indiscretion. How much longer he has to go is anyone's guess. His father remains in good health and is not interested in abdicating.

"A crown prince is always educated as the ideal model of the times," says author Hideaki Kase. Akihito drives (albeit only on the palace grounds). He speaks English. He likes smart clothing (double-breasted suits are a trademark). In some ways, as the Japanese joke has it, he is indistinguishable from the legions of salaried workers who inhabit the country's corporate offices.

He was born in 1933, following a succession of sisters whose arrival had so worried palace officials over the prospect of a male heir that they proposed -- unsuccessfully -- that Hirohito take a concubine. He was 12 when the war ended and got most of his education under the postwar imperial system in which the emperor is only a symbol of state.

"Compared to his father, he has always had a different sense of himself," says Toshiaki Kawahara, a journalist who formerly covered the court. "He has never been treated as a god, or having a god's character."

The prince's public statements tend to be as bland as his father's. But he has shown strength of character in action. In 1959, he broke tradition by becoming the first heir to the throne to marry outside court circles. His bride, Michiko Shoda, was the attractive daughter of a wealthy flour manufacturer. He also refused to follow the custom of separating children from their parents at an early age.

Their marriage was a sort of Charles and Diana phenomenon 25 years ago, with Michiko taking quickly to the duties of royalty while bringing a touch of glamor to the institution.

Last November they showed up at the Foreign Correspondents Club for a party and took a long turn on the dance floor. Japanese newspapers made much of the photos the next day, as no one could quite believe this burst of informality.

The couple has had three children. Eldest son Hiro, second in line for the throne, has spent two years at Oxford University (his specialty was water transportation on the Thames River during the 18th century). It was another first -- the first time someone in line to the throne has studied abroad.

Hiro is also asserting himself a bit, complaining in public recently that heavy police security kept him from having contact with ordinary people. From time to time, newspapers go to town with speculation about whom he will marry.

The closest thing to a gadfly in the imperial family is the emperor's brother, Prince Mikasa, who infuriated the far right some years ago by writing a book that called prewar court life a "prison without bars" and condemned in strong words excesses of the Japanese armed forces during World War II. Lately he has toned down. His son took up the banner in 1982, asking to be relieved of his imperial duties to allow him to devote more time to social welfare activities. His request was turned down.

The crown prince and princess have a heavy schedule of state ceremony that has taken them abroad repeatedly. They have toured the United States, Canada, Australia, New Zealand and countries in Southeast Asia and South America. Bit by bit, he is taking over duties from his father.

There is now talk of him making a good-will visit to South Korea, where Japan is trying to heal wounds left from its 35-year colonization there. But Korean opposition groups oppose it as strengthening the government. It is just the type of spat that the imperial household hates to be drawn into, but so far the official word is that planning is proceeding.