When the Emperor and Empress of Japan come to dinner, extra care is taken.

In 1974 Kikuchi Tomo of Tokyo invited their imperial highnesses to visit her summer place -- in 1976. She commissioned Fujimoto Yoshimichi, a leading ceramist, to make a special set of dishes for the event.

In two years of study and labor he produced a 230-piece, Western-style porcelain service for 15. "It was the most trying experience," Fujimoto said, "the work of a lifetime, which can never be repeated."

Well, the Emperor and Empress sat down to dinner, using European silver service, at a table with a centerpiece of roses. As they dined in privacy, the hostess and other guests ate elsewhere. "This is customary," said a friend of Kikuchi.

The Emperor and Empress no doubt admired the superb settings, which included milk cups because His Imperial Majesty drinks neither tea nor coffee, but were not expected to exclaim over them the way Aunt Samantha would require us to notice her new Noritake. They simply ate each dish from its appointed bowl or plate, and pronounced it all very fine, thank you.

And the dishes were washed and put away, never to be used or shown again.

Kikuchi, the leading patron of Japan's potters, later decided to include the Imperial Service in an exhibition of modern Japanese ceramics that opens this weekend at the Museum of Natural History.

The several hundred works, said to represent some of the finest accomplishments of the 101 best of Japan's 10,000 ceramists, are all from the personal collection of Kikuchi, the daughter of a coal tycoon. "If she isn't collecting you," one of her assistants said, "then you're not yet doing important work."

Fortunately for young artists, Kikuchi is always on the lookout for promising newcomers and nontraditionalists. The oldest piece in this selection dates from 1958, and many are all but hot from the kiln.

"If you can understand these objects, not just the styles and techniques, but the tradition the artists followed or chose not to follow, then you will understand Japan," said an aide. "We are not just offshore Chinese."

One hallmark of current Japanese ceramics is a preoccupation with the felicitous flaw. In extreme -- and prized -- cases, tops don't fit, sides are caved in, spouts and handles are crooked, glazes run rampant. It seems rather overstudied.

The majority of pieces, however, range from arresting to breathtaking, easily appreciated whether or not understood in terms of the 1,500-year history of the art. Exhibit designer Richard Molinaroli has dealt masterfully with an awkward space, particularly in his recreation of Kikuchi's teahouse, said to be the exemplification of the proper setting for the tea ceremony. JAPANESE CERAMICS TODAY -- Through April 13 at the Museum of Natural History (Constitution Avenue entrance). The film "The Living Treasures of Japan" will be shown at noon Friday in Baird Auditorium. Seizo Hayashiya, ceramics curator of the Tokyo National Museum, will lecture on "A Thousand Years of Japanese Ceramics" Friday at 8 and the tea ceremony will be demonstrated Saturday and Sunday at 2, also in Baird. Films will be shown in the Gallery Theater each weekend from 1 to 2 through April 3: on Saturdays, "Colored Nabeshima Ware" and "The Art and Meaning of Ikebana"; on Sundays, "Toyozo Arakawa: Japanese Potter" and "Kyoto Confections."